Infrared Spectra and Ab Initio Calculations for the F-−(CH4)n (n = 1−8) Anion Clusters

摘要: Infrared spectra of mass-selected F - -(CH 4 ) n (n = 1-8) clusters are recorded in the CH stretching region (2500-3100 cm -1 ). Spectra for 1-3 interpreted with aid ab initio calculations at MP2/6-311++G(2df 2p) level, which suggest that CH4 ligands bind to by equivalent, linear hydrogen bonds. Anharmonic frequencies and -CH determined using vibrational self-consistent field method second-order perturbation theory correction. The 1 complex is predicted have a C 3v structure single group bonded . Its spectrum exhibits parallel band associated vibration hydrogen-bonded red-shifted 380 from v free perpendicular asymmetric motion nonbonded groups, slightly 3 As increases, additional bands appear as result Fermi resonances between mode 2v overtone 2 + combination levels methane solvent molecules. For ≤ 8, it appears molecules accommodated first solvation shell, each being attached anion equivalent