TY  - JOUR
AU  - Veljković, Filip M.
AU  - Dimitrijević, Stevan P.
AU  - Dimitrijević, Silvana B.
AU  - Vurdelja, Borislava D.
AU  - Matović, Branko Z.
AU  - Stoiljković, Milovan M.
AU  - Kamberović, Željko J.
AU  - Veličković, Suzana R.
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5317
AB  - This work presents the perspective of applying the laser desorption/ionization mass spectrometry (LDI MS) for characterization the anode film of the Ag60Cu26Zn14, Ag58.5Cu31.5Pd10, and Ag63Cu27In10 alloys (at high concentrations of chloride ions in solutions). The reference LDI mass spectra of anode films of pure Ag and Cu have been used for the identification of product corrosion. Knowing the clusters detected in the reference spectra lead to the facilitating identification of the LDI mass spectrum of the sample and reduces the analysis time. The LDI MS analysis of these alloys revealed that the predominant corrosion product are AgCl (from AgnCln+1−/+, n = 1–3), and CuCl (from “superhalogen” CumCln− clusters, m = 1–2, n = 2–6); it also revealed Cu2(OH)3Cl (from Cu2(OH)(H2O)2+) and Cu2O (from Cu(H2O)+, Cu2O doped with chlorine). These results are in accordance with the X-ray diffraction and Raman analysis. The LDI MS spectra of alloys contain the additional peaks formed due to the mutual influences of different metals in the alloys (AgCuCl3− (AgCl-CuCl2−), AgCu2Cl4− (AgCl-CuCl-CuCl2−), and Ag2CuCl4− (AgCl-AgCl-CuCl−), which is consistent with the identified corrosion products. It should be noted that the LDI MS suggest the presence of CuCl2, which can be interpreted as the corrosion products retained in the porous films of alloys, and not detected by the other methods due to a small amount. The future theoretical and experimental studies of metal clusters, significant for metallurgy, can contribute that the LDI MS is becoming a powerful analytical tool for characterization the metal surfaces.
PB  - Elsevier B.V.
T2  - Arabian Journal of Chemistry
T1  - Prospective of the LDI MS to characterization the corrosion products of silver-copper alloys on an example of the Ag-Cu-X (X- Zn, Pd, In) system
IS  - 2
SP  - 104461
VL  - 16
DO  - 10.1016/j.arabjc.2022.104461
ER  - 

@article{
author = "Veljković, Filip M. and Dimitrijević, Stevan P. and Dimitrijević, Silvana B. and Vurdelja, Borislava D. and Matović, Branko Z. and Stoiljković, Milovan M. and Kamberović, Željko J. and Veličković, Suzana R.",
year = "2023",
abstract = "This work presents the perspective of applying the laser desorption/ionization mass spectrometry (LDI MS) for characterization the anode film of the Ag60Cu26Zn14, Ag58.5Cu31.5Pd10, and Ag63Cu27In10 alloys (at high concentrations of chloride ions in solutions). The reference LDI mass spectra of anode films of pure Ag and Cu have been used for the identification of product corrosion. Knowing the clusters detected in the reference spectra lead to the facilitating identification of the LDI mass spectrum of the sample and reduces the analysis time. The LDI MS analysis of these alloys revealed that the predominant corrosion product are AgCl (from AgnCln+1−/+, n = 1–3), and CuCl (from “superhalogen” CumCln− clusters, m = 1–2, n = 2–6); it also revealed Cu2(OH)3Cl (from Cu2(OH)(H2O)2+) and Cu2O (from Cu(H2O)+, Cu2O doped with chlorine). These results are in accordance with the X-ray diffraction and Raman analysis. The LDI MS spectra of alloys contain the additional peaks formed due to the mutual influences of different metals in the alloys (AgCuCl3− (AgCl-CuCl2−), AgCu2Cl4− (AgCl-CuCl-CuCl2−), and Ag2CuCl4− (AgCl-AgCl-CuCl−), which is consistent with the identified corrosion products. It should be noted that the LDI MS suggest the presence of CuCl2, which can be interpreted as the corrosion products retained in the porous films of alloys, and not detected by the other methods due to a small amount. The future theoretical and experimental studies of metal clusters, significant for metallurgy, can contribute that the LDI MS is becoming a powerful analytical tool for characterization the metal surfaces.",
publisher = "Elsevier B.V.",
journal = "Arabian Journal of Chemistry",
title = "Prospective of the LDI MS to characterization the corrosion products of silver-copper alloys on an example of the Ag-Cu-X (X- Zn, Pd, In) system",
number = "2",
pages = "104461",
volume = "16",
doi = "10.1016/j.arabjc.2022.104461"
}

Veljković, F. M., Dimitrijević, S. P., Dimitrijević, S. B., Vurdelja, B. D., Matović, B. Z., Stoiljković, M. M., Kamberović, Ž. J.,& Veličković, S. R.. (2023). Prospective of the LDI MS to characterization the corrosion products of silver-copper alloys on an example of the Ag-Cu-X (X- Zn, Pd, In) system. in Arabian Journal of Chemistry
Elsevier B.V.., 16(2), 104461.
https://doi.org/10.1016/j.arabjc.2022.104461

Veljković FM, Dimitrijević SP, Dimitrijević SB, Vurdelja BD, Matović BZ, Stoiljković MM, Kamberović ŽJ, Veličković SR. Prospective of the LDI MS to characterization the corrosion products of silver-copper alloys on an example of the Ag-Cu-X (X- Zn, Pd, In) system. in Arabian Journal of Chemistry. 2023;16(2):104461.
doi:10.1016/j.arabjc.2022.104461 .

Veljković, Filip M., Dimitrijević, Stevan P., Dimitrijević, Silvana B., Vurdelja, Borislava D., Matović, Branko Z., Stoiljković, Milovan M., Kamberović, Željko J., Veličković, Suzana R., "Prospective of the LDI MS to characterization the corrosion products of silver-copper alloys on an example of the Ag-Cu-X (X- Zn, Pd, In) system" in Arabian Journal of Chemistry, 16, no. 2 (2023):104461,
https://doi.org/10.1016/j.arabjc.2022.104461 . .

TY  - JOUR
AU  - Mitić, Marko
AU  - Milovanović, Milan
AU  - Veljković, Filip M.
AU  - Perić-Grujić, Aleksandra
AU  - Veličković, Suzana
AU  - Jerosimić, Stanka
PY  - 2020
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4512
AB  - In the present paper, the results of combined theoretical and experimental investigation of small non-stoichiometric bromine-doped potassium clusters are reported. Potassium-bromide clusters were obtained by the Knudsen cell combined with surface ionization in the temperature range of 1000-1600 K, and selected by a magnetic sector mass spectrometer. Positive ions of KnBr (n = 3-6) and KnBrn-1 (n = 3-5) clusters were detected for the first time in one set measurement. In order to reveal the geometrical structure of each type of detected cluster, the randomized search algorithm was employed to survey the (Born-Oppenheimer) potential energy surface of both the neutral and cationic KnBr(0,1+) (n = 1-6) and KnBrn-1(0,1+) (n=3 5) clusters, followed by Density functional theory geometry optimizations, and many lowest-energy conformational isomers are presented. From the total electronic energies of clusters computed by the ab initio RCCSD(T)/ECP10MDF(K),cc-pVTZ-PP(Br) method at obtained equilibrium nuclear geometries, the following stability parameters of clusters were computed: their relative energies, the adiabatic and vertical ionization energies, binding energies per atom, and dissociation energies. Both experimental and theoretical results have shown that the title clusters belong to the group of "superalkali" clusters.
PB  - Elsevier Science Sa, Lausanne
T2  - Journal of Alloys and Compounds
T1  - Theoretical and experimental study of small potassium-bromide KnBr(0,1+) (n=2-6) and KnBrn-1(0,1+) (n=3-5) clusters
VL  - 835
DO  - 10.1016/j.jallcom.2020.155301
ER  - 

@article{
author = "Mitić, Marko and Milovanović, Milan and Veljković, Filip M. and Perić-Grujić, Aleksandra and Veličković, Suzana and Jerosimić, Stanka",
year = "2020",
abstract = "In the present paper, the results of combined theoretical and experimental investigation of small non-stoichiometric bromine-doped potassium clusters are reported. Potassium-bromide clusters were obtained by the Knudsen cell combined with surface ionization in the temperature range of 1000-1600 K, and selected by a magnetic sector mass spectrometer. Positive ions of KnBr (n = 3-6) and KnBrn-1 (n = 3-5) clusters were detected for the first time in one set measurement. In order to reveal the geometrical structure of each type of detected cluster, the randomized search algorithm was employed to survey the (Born-Oppenheimer) potential energy surface of both the neutral and cationic KnBr(0,1+) (n = 1-6) and KnBrn-1(0,1+) (n=3 5) clusters, followed by Density functional theory geometry optimizations, and many lowest-energy conformational isomers are presented. From the total electronic energies of clusters computed by the ab initio RCCSD(T)/ECP10MDF(K),cc-pVTZ-PP(Br) method at obtained equilibrium nuclear geometries, the following stability parameters of clusters were computed: their relative energies, the adiabatic and vertical ionization energies, binding energies per atom, and dissociation energies. Both experimental and theoretical results have shown that the title clusters belong to the group of "superalkali" clusters.",
publisher = "Elsevier Science Sa, Lausanne",
journal = "Journal of Alloys and Compounds",
title = "Theoretical and experimental study of small potassium-bromide KnBr(0,1+) (n=2-6) and KnBrn-1(0,1+) (n=3-5) clusters",
volume = "835",
doi = "10.1016/j.jallcom.2020.155301"
}

Mitić, M., Milovanović, M., Veljković, F. M., Perić-Grujić, A., Veličković, S.,& Jerosimić, S.. (2020). Theoretical and experimental study of small potassium-bromide KnBr(0,1+) (n=2-6) and KnBrn-1(0,1+) (n=3-5) clusters. in Journal of Alloys and Compounds
Elsevier Science Sa, Lausanne., 835.
https://doi.org/10.1016/j.jallcom.2020.155301

Mitić M, Milovanović M, Veljković FM, Perić-Grujić A, Veličković S, Jerosimić S. Theoretical and experimental study of small potassium-bromide KnBr(0,1+) (n=2-6) and KnBrn-1(0,1+) (n=3-5) clusters. in Journal of Alloys and Compounds. 2020;835.
doi:10.1016/j.jallcom.2020.155301 .

Mitić, Marko, Milovanović, Milan, Veljković, Filip M., Perić-Grujić, Aleksandra, Veličković, Suzana, Jerosimić, Stanka, "Theoretical and experimental study of small potassium-bromide KnBr(0,1+) (n=2-6) and KnBrn-1(0,1+) (n=3-5) clusters" in Journal of Alloys and Compounds, 835 (2020),
https://doi.org/10.1016/j.jallcom.2020.155301 . .

TY  - JOUR
AU  - Radović, Ivana
AU  - Stajčić, Aleksandar
AU  - Radisavljević, Anđela
AU  - Veljković, Filip M.
AU  - Čebela, Maria
AU  - Mitić, Vojislav V.
AU  - Radojević, Vesna
PY  - 2020
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4435
AB  - Nowadays, there is a very high importance of composite research and variety of their applications in the modern world. In that sense, we researched hollow glass capillaries filled with dissolved Grubbs catalyst (GC) and dicyclopentadiene (DCPD) were incorporated into a fiber-reinforced epoxy with the aim of improving the flow of healing agents to the crack site. The morphological investigation of the crack site was performed using field emission scanning electron microscopy (FESEM), showing the difference between the samples depending on the used solvent. The software analysis of sample photographs has been performed by calculating the fractured/healed surface area of the samples, revealing that approximately 20% of the volume was affected by the impact. Fourier transform infrared spectroscopy (FTIR) revealed that poly (dicyclopentadiene) (PDCPD) formed at the healed interface. However, the FTIR investigation of catalyst stability in different solvents showed structural changes in GC and partial deactivation. The mechanical tests of the samples showed that a recovery of 60% after 24 h at room temperature could be achieved through the use of a solvent and very low concentration of GC. The performed research results are a good base to develop the model for predicting the processes and morphology, with the goal to design the final mechanical and in the future, thermal, properties in advance. This opens a new direction for future research in the field of composite healing.
PB  - Elsevier Science Sa, Lausanne
T2  - Materials Chemistry and Physics
T1  - Solvent effects on structural changes in self-healing epoxy composites
VL  - 256
DO  - 10.1016/j.matchemphys.2020.123761
ER  - 

@article{
author = "Radović, Ivana and Stajčić, Aleksandar and Radisavljević, Anđela and Veljković, Filip M. and Čebela, Maria and Mitić, Vojislav V. and Radojević, Vesna",
year = "2020",
abstract = "Nowadays, there is a very high importance of composite research and variety of their applications in the modern world. In that sense, we researched hollow glass capillaries filled with dissolved Grubbs catalyst (GC) and dicyclopentadiene (DCPD) were incorporated into a fiber-reinforced epoxy with the aim of improving the flow of healing agents to the crack site. The morphological investigation of the crack site was performed using field emission scanning electron microscopy (FESEM), showing the difference between the samples depending on the used solvent. The software analysis of sample photographs has been performed by calculating the fractured/healed surface area of the samples, revealing that approximately 20% of the volume was affected by the impact. Fourier transform infrared spectroscopy (FTIR) revealed that poly (dicyclopentadiene) (PDCPD) formed at the healed interface. However, the FTIR investigation of catalyst stability in different solvents showed structural changes in GC and partial deactivation. The mechanical tests of the samples showed that a recovery of 60% after 24 h at room temperature could be achieved through the use of a solvent and very low concentration of GC. The performed research results are a good base to develop the model for predicting the processes and morphology, with the goal to design the final mechanical and in the future, thermal, properties in advance. This opens a new direction for future research in the field of composite healing.",
publisher = "Elsevier Science Sa, Lausanne",
journal = "Materials Chemistry and Physics",
title = "Solvent effects on structural changes in self-healing epoxy composites",
volume = "256",
doi = "10.1016/j.matchemphys.2020.123761"
}

Radović, I., Stajčić, A., Radisavljević, A., Veljković, F. M., Čebela, M., Mitić, V. V.,& Radojević, V.. (2020). Solvent effects on structural changes in self-healing epoxy composites. in Materials Chemistry and Physics
Elsevier Science Sa, Lausanne., 256.
https://doi.org/10.1016/j.matchemphys.2020.123761

Radović I, Stajčić A, Radisavljević A, Veljković FM, Čebela M, Mitić VV, Radojević V. Solvent effects on structural changes in self-healing epoxy composites. in Materials Chemistry and Physics. 2020;256.
doi:10.1016/j.matchemphys.2020.123761 .

Radović, Ivana, Stajčić, Aleksandar, Radisavljević, Anđela, Veljković, Filip M., Čebela, Maria, Mitić, Vojislav V., Radojević, Vesna, "Solvent effects on structural changes in self-healing epoxy composites" in Materials Chemistry and Physics, 256 (2020),
https://doi.org/10.1016/j.matchemphys.2020.123761 . .

TY  - JOUR
AU  - Dimitrijević, Stevan
AU  - Vurdelja, Borislava D.
AU  - Dimitrijević, Silvana
AU  - Veljković, Filip M.
AU  - Kamberović, Željko
AU  - Veličković, Suzana
PY  - 2020
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4456
AB  - Corrosion products formed on the surface of two silver brazing alloys after the potentiostatic polarization in 3.5% sodium chloride solution were characterized by the standard methods such as, the X-ray diffraction, microRaman spectroscopy, and scanning electron microscopy with energy-dispersive spectroscopy. This paper presents the results of a laser desorption/ionization mass spectrometry (LDI MS) analysis as a new approach to the characterization of corrosion products. The potential of the anodic polarization was 0.5 V versus saturated calomel electrode, and the process duration was 300 s. The corrosion layers on both investigated alloys were similar in composition with cuprous chloride and silver chloride as the main components and had strong indications of cuprous oxide formation. The major difference between these two layers was the existence of zinc hydroxychioride as the corrosion product of Ag-Cu-Zn alloy. Palladium compounds were not found in the case of Ag-Cu-Pd alloy. The results of different methods have shown a good consistency. Complementarity between the used methods was useful in the interpretation of the results for each used method. This study has demonstrated that LDI MS can be used as an efficient additional method together with the traditional ones.
PB  - Walter de Gruyter Gmbh, Berlin
T2  - Corrosion Reviews
T1  - Complementary methods for characterization of the corrosion products on the surface of Ag60Cu26Zn14 and Ag58.5Cu31.5Pd10 brazing alloys
EP  - 125
IS  - 2
SP  - 111
VL  - 38
DO  - 10.1515/corrrev-2019-0067
ER  - 

@article{
author = "Dimitrijević, Stevan and Vurdelja, Borislava D. and Dimitrijević, Silvana and Veljković, Filip M. and Kamberović, Željko and Veličković, Suzana",
year = "2020",
abstract = "Corrosion products formed on the surface of two silver brazing alloys after the potentiostatic polarization in 3.5% sodium chloride solution were characterized by the standard methods such as, the X-ray diffraction, microRaman spectroscopy, and scanning electron microscopy with energy-dispersive spectroscopy. This paper presents the results of a laser desorption/ionization mass spectrometry (LDI MS) analysis as a new approach to the characterization of corrosion products. The potential of the anodic polarization was 0.5 V versus saturated calomel electrode, and the process duration was 300 s. The corrosion layers on both investigated alloys were similar in composition with cuprous chloride and silver chloride as the main components and had strong indications of cuprous oxide formation. The major difference between these two layers was the existence of zinc hydroxychioride as the corrosion product of Ag-Cu-Zn alloy. Palladium compounds were not found in the case of Ag-Cu-Pd alloy. The results of different methods have shown a good consistency. Complementarity between the used methods was useful in the interpretation of the results for each used method. This study has demonstrated that LDI MS can be used as an efficient additional method together with the traditional ones.",
publisher = "Walter de Gruyter Gmbh, Berlin",
journal = "Corrosion Reviews",
title = "Complementary methods for characterization of the corrosion products on the surface of Ag60Cu26Zn14 and Ag58.5Cu31.5Pd10 brazing alloys",
pages = "125-111",
number = "2",
volume = "38",
doi = "10.1515/corrrev-2019-0067"
}

Dimitrijević, S., Vurdelja, B. D., Dimitrijević, S., Veljković, F. M., Kamberović, Ž.,& Veličković, S.. (2020). Complementary methods for characterization of the corrosion products on the surface of Ag60Cu26Zn14 and Ag58.5Cu31.5Pd10 brazing alloys. in Corrosion Reviews
Walter de Gruyter Gmbh, Berlin., 38(2), 111-125.
https://doi.org/10.1515/corrrev-2019-0067

Dimitrijević S, Vurdelja BD, Dimitrijević S, Veljković FM, Kamberović Ž, Veličković S. Complementary methods for characterization of the corrosion products on the surface of Ag60Cu26Zn14 and Ag58.5Cu31.5Pd10 brazing alloys. in Corrosion Reviews. 2020;38(2):111-125.
doi:10.1515/corrrev-2019-0067 .

Dimitrijević, Stevan, Vurdelja, Borislava D., Dimitrijević, Silvana, Veljković, Filip M., Kamberović, Željko, Veličković, Suzana, "Complementary methods for characterization of the corrosion products on the surface of Ag60Cu26Zn14 and Ag58.5Cu31.5Pd10 brazing alloys" in Corrosion Reviews, 38, no. 2 (2020):111-125,
https://doi.org/10.1515/corrrev-2019-0067 . .

TY  - JOUR
AU  - Milovanović, Branislav
AU  - Milovanović, Milan
AU  - Veličković, Suzana
AU  - Veljković, Filip M.
AU  - Perić-Grujić, Aleksandra
AU  - Jerosimić, Stanka
PY  - 2019
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4053
AB  - Small heterogeneous potassium-iodide clusters are investigated by means of ab initio electronic structural methods together with experimental production and detection in mass spectrometry. Experiments were done by using Knudsen cell mass spectrometry (KCMS) modification method, which provided simultaneous generating of all KnI0,+1 (n = 2-6) clusters at once. Clusters with more than two potassium atoms are produced for the first time. The lowest lying isomers of those KnI0,+1 (n = 2-6) clusters were found by using a random-kick procedure. The best description of growth of these clusters is the addition of one potassium atom to a smaller-neighbor cluster. Subsequently, stability of these species was examined. In spite of general trend of decreasing of binding energies, the closed-shell species have slightly larger stability with respect to the open-shell species. Alternation of dissociation energies between closed-shell and open-shell clusters is presented. Experimental setup also allows determination of ionization energies of clusters: the obtained values are in the range of 3.46-3.98 eV, which classify these clusters as "superalkali." For closed-shell clusters, the theoretical adiabatic ionization energies are close to experimental values, whereas in the case of open-shell clusters, the vertical ionization energies are those that are close to experimental values.
PB  - Wiley, Hoboken
T2  - International Journal of Quantum Chemistry
T1  - Theoretical and experimental investigation of geometry and stability of small potassium-iodide KnI (n=2-6) clusters
IS  - 22
VL  - 119
DO  - 10.1002/qua.26009
ER  - 

@article{
author = "Milovanović, Branislav and Milovanović, Milan and Veličković, Suzana and Veljković, Filip M. and Perić-Grujić, Aleksandra and Jerosimić, Stanka",
year = "2019",
abstract = "Small heterogeneous potassium-iodide clusters are investigated by means of ab initio electronic structural methods together with experimental production and detection in mass spectrometry. Experiments were done by using Knudsen cell mass spectrometry (KCMS) modification method, which provided simultaneous generating of all KnI0,+1 (n = 2-6) clusters at once. Clusters with more than two potassium atoms are produced for the first time. The lowest lying isomers of those KnI0,+1 (n = 2-6) clusters were found by using a random-kick procedure. The best description of growth of these clusters is the addition of one potassium atom to a smaller-neighbor cluster. Subsequently, stability of these species was examined. In spite of general trend of decreasing of binding energies, the closed-shell species have slightly larger stability with respect to the open-shell species. Alternation of dissociation energies between closed-shell and open-shell clusters is presented. Experimental setup also allows determination of ionization energies of clusters: the obtained values are in the range of 3.46-3.98 eV, which classify these clusters as "superalkali." For closed-shell clusters, the theoretical adiabatic ionization energies are close to experimental values, whereas in the case of open-shell clusters, the vertical ionization energies are those that are close to experimental values.",
publisher = "Wiley, Hoboken",
journal = "International Journal of Quantum Chemistry",
title = "Theoretical and experimental investigation of geometry and stability of small potassium-iodide KnI (n=2-6) clusters",
number = "22",
volume = "119",
doi = "10.1002/qua.26009"
}

Milovanović, B., Milovanović, M., Veličković, S., Veljković, F. M., Perić-Grujić, A.,& Jerosimić, S.. (2019). Theoretical and experimental investigation of geometry and stability of small potassium-iodide KnI (n=2-6) clusters. in International Journal of Quantum Chemistry
Wiley, Hoboken., 119(22).
https://doi.org/10.1002/qua.26009

Milovanović B, Milovanović M, Veličković S, Veljković FM, Perić-Grujić A, Jerosimić S. Theoretical and experimental investigation of geometry and stability of small potassium-iodide KnI (n=2-6) clusters. in International Journal of Quantum Chemistry. 2019;119(22).
doi:10.1002/qua.26009 .

Milovanović, Branislav, Milovanović, Milan, Veličković, Suzana, Veljković, Filip M., Perić-Grujić, Aleksandra, Jerosimić, Stanka, "Theoretical and experimental investigation of geometry and stability of small potassium-iodide KnI (n=2-6) clusters" in International Journal of Quantum Chemistry, 119, no. 22 (2019),
https://doi.org/10.1002/qua.26009 . .

TY  - JOUR
AU  - Veljković, Filip M.
AU  - Perić-Grujić, Aleksandra
AU  - Veličković, Suzana
PY  - 2016
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3244
AB  - Knudsen effusion mass spectrometry or high-temperature method of mass spectrometry for decades gives new information about saturated vapor of hardly volatile compounds and it is an important method in the discovery of many new molecules, radicals, ions and clusters present in the gas phase. Since pioneering works until now, this method has been successfully applied to a large number of systems (ores, oxides, ceramics, glass materials, borides, carbides, sulfides, nitrates, metals, fullerenes, etc.) which led to the establishment of various research branches such as chemistry of clusters. This paper describes the basic principles of Knudsen cell use for both identification of chemical species created in the process of evaporation and determination of their ionization energies. Depending on detected ions intensities and the partial pressure of each gaseous component, as well as on changes in partial pressure with temperature, Knudsen cell mass spectrometry enables the determination of thermodynamic parameters of the tested system. A special attention is paid to its application in the field of small heterogeneous and homogeneous clusters of alkali metals. Furthermore, experimental results for thermodynamic parameters of some clusters, as well as capabilities of non-standard ways of using Knudsen cells in the process of synthesis of new clusters are presented herein.
PB  - Savez hemijskih inženjera, Beograd
T2  - Hemijska industrija
T1  - Mass spectrometric production of heterogeneous metal clusters using knudsen cell
EP  - 637
IS  - 6
SP  - 629
VL  - 70
DO  - 10.2298/HEMIND150922070V
ER  - 

@article{
author = "Veljković, Filip M. and Perić-Grujić, Aleksandra and Veličković, Suzana",
year = "2016",
abstract = "Knudsen effusion mass spectrometry or high-temperature method of mass spectrometry for decades gives new information about saturated vapor of hardly volatile compounds and it is an important method in the discovery of many new molecules, radicals, ions and clusters present in the gas phase. Since pioneering works until now, this method has been successfully applied to a large number of systems (ores, oxides, ceramics, glass materials, borides, carbides, sulfides, nitrates, metals, fullerenes, etc.) which led to the establishment of various research branches such as chemistry of clusters. This paper describes the basic principles of Knudsen cell use for both identification of chemical species created in the process of evaporation and determination of their ionization energies. Depending on detected ions intensities and the partial pressure of each gaseous component, as well as on changes in partial pressure with temperature, Knudsen cell mass spectrometry enables the determination of thermodynamic parameters of the tested system. A special attention is paid to its application in the field of small heterogeneous and homogeneous clusters of alkali metals. Furthermore, experimental results for thermodynamic parameters of some clusters, as well as capabilities of non-standard ways of using Knudsen cells in the process of synthesis of new clusters are presented herein.",
publisher = "Savez hemijskih inženjera, Beograd",
journal = "Hemijska industrija",
title = "Mass spectrometric production of heterogeneous metal clusters using knudsen cell",
pages = "637-629",
number = "6",
volume = "70",
doi = "10.2298/HEMIND150922070V"
}

Veljković, F. M., Perić-Grujić, A.,& Veličković, S.. (2016). Mass spectrometric production of heterogeneous metal clusters using knudsen cell. in Hemijska industrija
Savez hemijskih inženjera, Beograd., 70(6), 629-637.
https://doi.org/10.2298/HEMIND150922070V

Veljković FM, Perić-Grujić A, Veličković S. Mass spectrometric production of heterogeneous metal clusters using knudsen cell. in Hemijska industrija. 2016;70(6):629-637.
doi:10.2298/HEMIND150922070V .

Veljković, Filip M., Perić-Grujić, Aleksandra, Veličković, Suzana, "Mass spectrometric production of heterogeneous metal clusters using knudsen cell" in Hemijska industrija, 70, no. 6 (2016):629-637,
https://doi.org/10.2298/HEMIND150922070V . .

TY  - JOUR
AU  - Veljković, Filip M.
AU  - Đustebek, Jasmina B.
AU  - Veljković, Miomir V.
AU  - Veličković, Suzana
AU  - Perić-Grujić, Aleksandra
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2140
AB  - RATIONALE The very small clusters of the type KnF are of particular importance since their first ionization energies (IEs) are lower than those of the alkali metal atoms. Theoretical calculation has demonstrated that this kind of cluster represents a potential 'building block' for cluster-assembly materials with unique structural, electronic, optical, magnetic, and thermodynamic properties. To date, however, there have been no experimental results on the IEs of KnF (n  gt 2) clusters. METHOD KnF (n?=?26) clusters were produced by the evaporation of a solid potassium fluoride salt using a modified thermal ionization source of modified design, and mass selected by a magnetic sector mass spectrometer where their IEs were determined. RESULTS Clusters KnF (n?=?36) were detected for the first time. The order of the ion intensities was K2F+ gt ? gt ?K4F+ gt ? gt ?K3F+K6F+? gt ?K5F+. The determined IEs were 3.99 +/- 0.20?eV for K2F, 4.16 +/- 0.20?eV for K3F, 4.27 +/- 0.20?eV for K4F, 4.22 +/- 0.20?eV for K5F, and 4.31 +/- 0.20?eV for K6F. The IEs of KnF increase slightly with the increase in potassium atom number from 2 to 6. We also observed that the presence of a fluorine atom leads to increasing ionization energy of bare metal potassium clusters. CONCLUSIONS The modified thermal ionization source provides an efficient way of obtaining the fluorine-doped potassium clusters. These results also present experimental proof that KnF (n?=?26) clusters belong to the group of 'superalkali' species.
PB  - Wiley, Hoboken
T2  - Rapid Communications in Mass Spectrometry
T1  - Production and ionization energies of KnF (n=2-6) clusters by thermal ionization mass spectrometry
EP  - 1766
IS  - 16
SP  - 1761
VL  - 26
DO  - 10.1002/rcm.6284
ER  - 

@article{
author = "Veljković, Filip M. and Đustebek, Jasmina B. and Veljković, Miomir V. and Veličković, Suzana and Perić-Grujić, Aleksandra",
year = "2012",
abstract = "RATIONALE The very small clusters of the type KnF are of particular importance since their first ionization energies (IEs) are lower than those of the alkali metal atoms. Theoretical calculation has demonstrated that this kind of cluster represents a potential 'building block' for cluster-assembly materials with unique structural, electronic, optical, magnetic, and thermodynamic properties. To date, however, there have been no experimental results on the IEs of KnF (n  gt 2) clusters. METHOD KnF (n?=?26) clusters were produced by the evaporation of a solid potassium fluoride salt using a modified thermal ionization source of modified design, and mass selected by a magnetic sector mass spectrometer where their IEs were determined. RESULTS Clusters KnF (n?=?36) were detected for the first time. The order of the ion intensities was K2F+ gt ? gt ?K4F+ gt ? gt ?K3F+K6F+? gt ?K5F+. The determined IEs were 3.99 +/- 0.20?eV for K2F, 4.16 +/- 0.20?eV for K3F, 4.27 +/- 0.20?eV for K4F, 4.22 +/- 0.20?eV for K5F, and 4.31 +/- 0.20?eV for K6F. The IEs of KnF increase slightly with the increase in potassium atom number from 2 to 6. We also observed that the presence of a fluorine atom leads to increasing ionization energy of bare metal potassium clusters. CONCLUSIONS The modified thermal ionization source provides an efficient way of obtaining the fluorine-doped potassium clusters. These results also present experimental proof that KnF (n?=?26) clusters belong to the group of 'superalkali' species.",
publisher = "Wiley, Hoboken",
journal = "Rapid Communications in Mass Spectrometry",
title = "Production and ionization energies of KnF (n=2-6) clusters by thermal ionization mass spectrometry",
pages = "1766-1761",
number = "16",
volume = "26",
doi = "10.1002/rcm.6284"
}

Veljković, F. M., Đustebek, J. B., Veljković, M. V., Veličković, S.,& Perić-Grujić, A.. (2012). Production and ionization energies of KnF (n=2-6) clusters by thermal ionization mass spectrometry. in Rapid Communications in Mass Spectrometry
Wiley, Hoboken., 26(16), 1761-1766.
https://doi.org/10.1002/rcm.6284

Veljković FM, Đustebek JB, Veljković MV, Veličković S, Perić-Grujić A. Production and ionization energies of KnF (n=2-6) clusters by thermal ionization mass spectrometry. in Rapid Communications in Mass Spectrometry. 2012;26(16):1761-1766.
doi:10.1002/rcm.6284 .

Veljković, Filip M., Đustebek, Jasmina B., Veljković, Miomir V., Veličković, Suzana, Perić-Grujić, Aleksandra, "Production and ionization energies of KnF (n=2-6) clusters by thermal ionization mass spectrometry" in Rapid Communications in Mass Spectrometry, 26, no. 16 (2012):1761-1766,
https://doi.org/10.1002/rcm.6284 . .

TY  - JOUR
AU  - Veljković, Filip M.
AU  - Đustebek, Jasmina B.
AU  - Veljković, Miomir V.
AU  - Perić-Grujić, Aleksandra
AU  - Veličković, Suzana
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2122
AB  - The theoretical calculations have predicted that nonmetal-doped potassium clusters can be used in the synthesis of a new class of charge-transfer salts which can be considered as potential building blocks for the assembly of novel nanostructured material. In this work, KnCl (n?=?26) and KnCln-1 (n?=?3 and 4) clusters were produced by vaporization of a solid potassium chloride salt in a thermal ionization mass spectrometry. The ionization energies (IEs) were measured, and found to be 3.64?+/-?0.20?eV for K2Cl, 3.67?+/-?0.20?eV for K3Cl, 3.62?+/-?0.20?eV for K4Cl, 3.57?+/-?0.20?eV for K5Cl, 3.69?+/-?0.20?eV for K6Cl, 3.71?+/-?0.20?eV for K3Cl2 and 3.72?+/-?0.20?eV for K4Cl3. The KnCl+ (n?=?36) clusters were detected for the first time in a cluster beam generated by the thermal ionization source of modified design. Also, this work is the first to report experimentally obtained values of IEs for KnCl+ (n?=?36) and KnCln-1+ (n?=?3 and 4) clusters. The ionization energies for KnCl+ and KnCln-1+ clusters are much lower than the 4.34?eV of the potassium atom; hence, these clusters should be classified as superalkali species.
PB  - Wiley, Hoboken
T2  - Journal of Mass Spectrometry
T1  - Study of small chlorine-doped potassium clusters by thermal ionization mass spectrometry
EP  - 1499
IS  - 11
SP  - 1495
VL  - 47
DO  - 10.1002/jms.3076
ER  - 

@article{
author = "Veljković, Filip M. and Đustebek, Jasmina B. and Veljković, Miomir V. and Perić-Grujić, Aleksandra and Veličković, Suzana",
year = "2012",
abstract = "The theoretical calculations have predicted that nonmetal-doped potassium clusters can be used in the synthesis of a new class of charge-transfer salts which can be considered as potential building blocks for the assembly of novel nanostructured material. In this work, KnCl (n?=?26) and KnCln-1 (n?=?3 and 4) clusters were produced by vaporization of a solid potassium chloride salt in a thermal ionization mass spectrometry. The ionization energies (IEs) were measured, and found to be 3.64?+/-?0.20?eV for K2Cl, 3.67?+/-?0.20?eV for K3Cl, 3.62?+/-?0.20?eV for K4Cl, 3.57?+/-?0.20?eV for K5Cl, 3.69?+/-?0.20?eV for K6Cl, 3.71?+/-?0.20?eV for K3Cl2 and 3.72?+/-?0.20?eV for K4Cl3. The KnCl+ (n?=?36) clusters were detected for the first time in a cluster beam generated by the thermal ionization source of modified design. Also, this work is the first to report experimentally obtained values of IEs for KnCl+ (n?=?36) and KnCln-1+ (n?=?3 and 4) clusters. The ionization energies for KnCl+ and KnCln-1+ clusters are much lower than the 4.34?eV of the potassium atom; hence, these clusters should be classified as superalkali species.",
publisher = "Wiley, Hoboken",
journal = "Journal of Mass Spectrometry",
title = "Study of small chlorine-doped potassium clusters by thermal ionization mass spectrometry",
pages = "1499-1495",
number = "11",
volume = "47",
doi = "10.1002/jms.3076"
}

Veljković, F. M., Đustebek, J. B., Veljković, M. V., Perić-Grujić, A.,& Veličković, S.. (2012). Study of small chlorine-doped potassium clusters by thermal ionization mass spectrometry. in Journal of Mass Spectrometry
Wiley, Hoboken., 47(11), 1495-1499.
https://doi.org/10.1002/jms.3076

Veljković FM, Đustebek JB, Veljković MV, Perić-Grujić A, Veličković S. Study of small chlorine-doped potassium clusters by thermal ionization mass spectrometry. in Journal of Mass Spectrometry. 2012;47(11):1495-1499.
doi:10.1002/jms.3076 .

Veljković, Filip M., Đustebek, Jasmina B., Veljković, Miomir V., Perić-Grujić, Aleksandra, Veličković, Suzana, "Study of small chlorine-doped potassium clusters by thermal ionization mass spectrometry" in Journal of Mass Spectrometry, 47, no. 11 (2012):1495-1499,
https://doi.org/10.1002/jms.3076 . .

TY  - JOUR
AU  - Veličković, Suzana
AU  - Veljković, Filip M.
AU  - Perić-Grujić, Aleksandra
AU  - Radak, Bojan
AU  - Veljković, Miomir V.
PY  - 2011
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1859
AB  - The electronic structure and properties of dipotassiummonohalides are important for understanding the unique physical and chemical behavior of MnX systems. In the present study, K2X (here X=F, Cl, Br, I) clusters were generated in the vapor over salts of the corresponding potassium halide, using a magnetic sector thermal ionization mass spectrometer. The ionization energies obtained for K2F, K2Cl, K2Br, and K2I molecules were 3.82 +/- 0.1eV, 3.68 +/- 0.1eV, 3.95 +/- 0.1eV, and 3.92 +/- 0.1, respectively. These experimental values of ionization energies for K2X (X=F, Br, and I) are presented for the first time. The ionization energy of K2Cl determined by thermal ionization corresponds to previous results obtained by photoionization mass spectrometry, and it agrees with the theoretical ionization energy calculated by the ab initio method. The presently obtained results support previous theoretical predictions that the excess electron in dipotassiummonohalide clusters is delocalized over two potassium atoms, which is characteristic for F-center clusters.
PB  - Wiley, Hoboken
T2  - Rapid Communications in Mass Spectrometry
T1  - Ionization energies of K2X (X=F, Cl, Br, I) clusters
EP  - 2332
IS  - 16
SP  - 2327
VL  - 25
DO  - 10.1002/rcm.5128
ER  - 

@article{
author = "Veličković, Suzana and Veljković, Filip M. and Perić-Grujić, Aleksandra and Radak, Bojan and Veljković, Miomir V.",
year = "2011",
abstract = "The electronic structure and properties of dipotassiummonohalides are important for understanding the unique physical and chemical behavior of MnX systems. In the present study, K2X (here X=F, Cl, Br, I) clusters were generated in the vapor over salts of the corresponding potassium halide, using a magnetic sector thermal ionization mass spectrometer. The ionization energies obtained for K2F, K2Cl, K2Br, and K2I molecules were 3.82 +/- 0.1eV, 3.68 +/- 0.1eV, 3.95 +/- 0.1eV, and 3.92 +/- 0.1, respectively. These experimental values of ionization energies for K2X (X=F, Br, and I) are presented for the first time. The ionization energy of K2Cl determined by thermal ionization corresponds to previous results obtained by photoionization mass spectrometry, and it agrees with the theoretical ionization energy calculated by the ab initio method. The presently obtained results support previous theoretical predictions that the excess electron in dipotassiummonohalide clusters is delocalized over two potassium atoms, which is characteristic for F-center clusters.",
publisher = "Wiley, Hoboken",
journal = "Rapid Communications in Mass Spectrometry",
title = "Ionization energies of K2X (X=F, Cl, Br, I) clusters",
pages = "2332-2327",
number = "16",
volume = "25",
doi = "10.1002/rcm.5128"
}

Veličković, S., Veljković, F. M., Perić-Grujić, A., Radak, B.,& Veljković, M. V.. (2011). Ionization energies of K2X (X=F, Cl, Br, I) clusters. in Rapid Communications in Mass Spectrometry
Wiley, Hoboken., 25(16), 2327-2332.
https://doi.org/10.1002/rcm.5128

Veličković S, Veljković FM, Perić-Grujić A, Radak B, Veljković MV. Ionization energies of K2X (X=F, Cl, Br, I) clusters. in Rapid Communications in Mass Spectrometry. 2011;25(16):2327-2332.
doi:10.1002/rcm.5128 .

Veličković, Suzana, Veljković, Filip M., Perić-Grujić, Aleksandra, Radak, Bojan, Veljković, Miomir V., "Ionization energies of K2X (X=F, Cl, Br, I) clusters" in Rapid Communications in Mass Spectrometry, 25, no. 16 (2011):2327-2332,
https://doi.org/10.1002/rcm.5128 . .