AB-INITIO INVESTIGATION OF THE ATMOSPHERIC MOLECULE BROMINE NITRATE -EQUILIBRIUM STRUCTURE, VIBRATIONAL-SPECTRUM, AND HEAT OF FORMATION

The equilibrium structure, dipole moment, harmonic vibrational frequen cies, and infrared intensities of BrONO2 are determined using the CCSD (T) (singles and doubles coupled-cluster theory plus a perturbational estimate of the effects of connected triple excitations) electronic st ructure method in conjunction with a TZ2P (triple zeta double polarize d) basis set. The heat of formation of BrONO2 is predicted (10.1 kcal/ mol at 298.15 K) using isodesmic reactions involving ClONO2, HONO2, HO Br, H2O, and HOCl. In addition, we draw attention to the importance of the reaction of O-3 With BrONO2 in relation to ozone layer depletion and stratospheric reservoirs of bromine. (C) 1998 American Institute o f Physics.