Complexes of LiF and LiCl with LiF, LiCl, LiH, HF, HCl, H2, Li2, F2, Cl2, FCl, H2O and NH3. Structures, energies and vibrational frequencies

Abstract

Using coupled cluster calculations with quadruple-zeta basis sets optimal structures and dissociation energies were obtained for complexes of LiF and LiCl with LiH, HF, HCl, H2, Li2, F2, Cl2, FCl, H2O and NH3. Structures for LiF-LiF and LiCl-LiCl have D2h symmetry, while the structure of LiF-LiCl, as well as structures of LiF and LiCl with LiH, HF and Li2 are cyclic, with C2v symmetry. Most other systems have Cs symmetry, many in near-cyclic form. The largest dissociation energy of 21,304 cm−1 was obtained for LiF-LiF. Dissociation energies for LiCl-LiCl and for cyclic C2v systems range from about 10,000 to 20,000 cm−1. For cyclic systems with D2h and C2v symmetries harmonic vibrational frequencies cannot be related to monomer frequencies. Their higher frequencies, however, are close to frequencies of triatomic Li-Y-Li, with Y = H, F, Cl, and to frequencies of F-H-F-.