Theoretical and experimental evaluation of K2Br+ and K3Br+ clusters' ionization energies

In current study, a non-stoichiometric bromine-doped potassium K2Br+and K3Br+clusters are generated by combining a Knudsen effusion cell as a chemical reactor with thermal or surface ionization,and selected by a magnetic sector mass spectrometer. Furthermore, their ionization energies (IEs) are calculated for the first time using B3LYP/9-ve PP(K),cc-pVTZ-PP(Br) level of theory. Herein, presented results indicate that experimentally obtained IEs by Ionov equation, 4.10 ± 0.20 eV for K2Br+, and 4.03 ± 0.20 eV for K3Br+, are in consistence with their theoretically determined IEs.Physical chemistry 2016 : 13th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-30 September 2016

Variational calculation of the vibronic spectrum in the X2Пu electronic state of C6-

A variational approach for ab initio handling of the Renner–Teller effect in six-atomic molecules with linear equilibrium geometry is elaborated. A very simple model Hamiltonian suitable for the description of small-amplitude bending vibrations in Π electronic states of arbitrary spin multiplicity was employed. The computer program developed within the framework of the present study was tested on the example of the X 2Πu state of C6 –. The results are compared with those generated in corresponding perturbative calculations. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172040

Theoretical and experimental investigation of geometry and stability of small potassium-iodide KnI (n=2-6) clusters

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

Theoretical and experimental study of small potassium-bromide KnBr(0,1+) (n=2-6) and KnBrn-1(0,1+) (n=3-5) clusters

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