Difluorophosphaazirine and other CF2NP isomers

Stationary points on the lowest energy spin-singlet potential energy surfac e of CF2NP are characterized using correlated ab initio electronic structur e methods. The geometrical parameters and harmonic vibrational frequencies of six new local minima, besides the previously studied cyanodifluorophosph ine, are identified at the MP2/cc-pVDZ level. Relative energies are obtaine d at the CCSD(T)/cc-pVTZ level. It is shown that difluorophosphaazirine, is ocyanodifluorophosphine and one additional isomer are stable, relative to d issociation products. Two of the six new isomers are metastable, and the re maining isomer is nearly isenergetic with the dissociation products. All re levant isomerization transition states have been located and show that the three thermodynamically stable isomers may also be expected to be reasonabl y stable kinetically. (C) 2001 Elsevier Science B.V. AU rights reserved.