An Investigation of the BCP Potential Energy Surface

Abstract

The singlet and triplet potential energy surfaces (PESs) of boron−carbon−phosphorus (BCP) isomers were investigated, using various theoretical methods. Geometries of the minima and transition states on the PES were optimized at the B3LYP/6-311+G(2df) and CASSCF(12,12)/6-311+G(2df) levels, and single-point calculations were made at the CASPT2/ANO-L level, to consider dynamic electron correlation effects. The most-stable isomer was linear singlet BCP (1Σ+); its calculated heat of formation (Δf H°, 0 K) is 150.5 ± 2 kcal/mol. Study of the fragmentation processes in BCP revealed that the bond enthalpies of the B−C and C−P bonds in BCP (1Σ+) at 0 K are 111.7 and 128.9 kcal/mol, respectively, at the CASPT2/ANO-L level. A possible crossing mechanism between two electronic states (3A‘ and 3A‘ ‘) is discussed, and Renner−Teller species with 3Π state symmetry are investigated.