A DENSITY-FUNCTIONAL STUDY OF BORANE AND ALANE MONOAMMONIATE (BH3NH3,ALH3NH3)

Molecular structures, harmonic vibrational frequencies, dissociation e nergies, and barriers to internal rotation have been determined using a Gaussian density functional method. Both local and nonlocal levels o f theory have been employed. The calculated equilibrium geometry and h armonic vibrational frequencies for BH3NH3 compare well with those det ermined by microwave and infrared experiments. The rotational barrier is found to be 2.09 kcal/mol in very good agreement with the experimen tal data The calculated properties for ammonia-alane (AlH3NH3) are com pared with those obtained previously from high level correlated method s. (C) 1995 American Institute of Physics.