Journal of Chemical Physics, Vol.106, No.8, 3280-3286, 1997
The Dissociation-Energies of NF(X(3)Sigma(-)) and Ncl(X(3)Sigma(-))
We have computed potential energy functions for the ground states (X (3) Sigma(-)) of NF and NCl using a series of correlation consistent basis sets ranging from double to sextuple zeta quality and including core-valence correlation effects in conjunction with coupled-cluster single and double excitations with perturbative treatment of triple excitations [CCSD(T)] and large internally contracted multireference configuration interaction (icMRCI) wave functions. The best estimates for the dissociation energies (D-e’s) are 76.6+/-1.3 kcal/mol for NF and 64.6+/-1.3 kcal/mol for NCl, respectively. Our results suggest that previous experimental estimates for the dissociation energy of NCl are in error by as much as 15 kcal/mol. The calculated spectroscopic constants for NF and NCl are in good agreement with the measured constants.
Keywords:CONFIGURATION-INTERACTION CALCULATIONS;MOLECULAR WAVE-FUNCTIONS;GAUSSIAN-BASIS SETS;SIZE-EXTENSIVE MODIFICATION;BENCHMARK CALCULATIONS;GEOMETRICAL STRUCTURE;ELECTRONIC-STRUCTURE;DIATOMIC HYDRIDES;RADICALS-NF;AB-INITIO