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

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, H-2, Li-2, F-2, Cl-2, FCl, H2O and NH3. Structures for LiF-LiF and LiCl-LiCl have D-2h symmetry, while the structure of LiF-LiCl, as well as structures of LiF and LiCl with LiH, HF and Li-2 are cyclic, with C-2v symmetry. Most other systems have C-s 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 C-2v systems range from about 10,000 to 20,000 cm(-1). For cyclic systems with D-2h and C-2v 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-.