Ab initio calculations of the anionic sodium-ammonia complex

The structure, stability and Vibrational frequencies of(NaNH3)(-) and (NaND3)(-) are examined by ab initio MP2 and CISD methods. It was found that the two C-3v isomers I and II have an Na-... NH3 dissociation energy D-e= 1135 cm(-1) (I) and D-e= 1028 cm(-1) (II). However, their vibrational frequencies are quite different. After consideration of the zero-point energy, the dissociation energy D-0 of isomer II is slightly larger than for isomer I. (C) 1997 Elsevier Science B.V.