Study of small chlorine-doped potassium clusters by thermal ionization mass spectrometry

摘要

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, K_nCl (n = 2-6) and K _nCl_(n-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 K_2Cl, 3.67 ± 0.20 eV for K_3Cl, 3.62 ± 0.20 eV for K_4Cl, 3.57 ± 0.20 eV for K _5Cl, 3.69 ± 0.20 eV for K_6Cl, 3.71 ± 0.20 eV for K_3Cl_2 and 3.72 ± 0.20 eV for K _4Cl_3. The K_nCl~+ (n = 3-6) 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 K_nCl~+ (n = 3-6) and K_nCln_(-1) + (n = 3 and 4) clusters. The ionization energies for K_nCl~+ and K_nCl _(n-1) ~+ clusters are much lower than the 4.34 eV of the potassium atom; hence, these clusters should be classified as 'superalkali' species.