A theoretical study of the C-H center dot center dot center dot N hydrogenbond in the methane-ammonia complex

The C-H...N hydrogen bond in the methane-ammonia complex is studied by dete rmining its bond dissociation energy (BDE) and the n(N) --> sigma*(C-H) int eraction. At the MP2(Full)/6-311 ++ G(3df,2p) level of theory with basis se t superposition error (BSSE) correction, the BDE was determined to be 2.5 k J mol(-1). The n(N) --> sigma*(C-H) interaction at this level of theory was found to he 3.7 kJ mol(-1) by natural bond orbital (NBO) analysis. It was also found that the NBO values are in general higher than the BDE values wi th BSSE correction when they are compared at the same level of theory. (C) 2000 Elsevier Science B.V. All rights reserved,