A SYSTEMATIC AB-INITIO INVESTIGATION OF THE OPEN AND RING STRUCTURES OF OZONE

The energy difference between the open and the ring isomer of ozone as well as the dissociation energy (O-3((X) over tilde (1)A(1)) --> O-2( X, (3)Sigma(g)(-))+ O(P-3)) have been determined at the CCSD(T), MR-CI SD and MR-AQCC levels of theory. Using correlation consistent basis se ts up to quintuple-zeta quality, the estimated complete basis set limi ts for CCSD(T) and MR-AQCC lie within 1 kcal/mol of the experimental v alue of 26.1 +/- 0.4 kcal/mol and place the ring isomer by 4.8 and 5.3 kcal/mol, respectively, above the dissociation Limit. Zero-point vibr ational corrections increase the latter two values by 1.4 kcal/mol. (C ) 1998 Elsevier Science B.V. All rights reserved.