ABINITIO STUDY OF THE WEAKLY BONDED CO-CL2 COMPLEX

Ab initio structure and vibrational frequency calculations have been p erformed on the weakly bonded CO-Cl2 complex at the SCF and MP2 levels of approximation. Minima were found for the two linear structures, sp ecifically CO-Cl2 and OC-Cl2, with the latter being slightly more stab le than the former. In addition, minima were found for two nonlinear s tructures, one T-shaped and the other essentially parallel. In the T-s haped structure, the oxygen is very weakly bonded to the chlorines (C2 v symmetry). The parallel isomer is slightly lower in energy than the T-shaped structure; however, both of the nonlinear isomers are less st able then either of the linear isomers. The calculated properties of t he OC-Cl2 isomer are in excellent agreement with experimental results reported earlier, lending further support to the conclusion that the s tructure of the experimentally observed isomer is OC-Cl2 rather than C O-Cl2.