On the conversion XCN ⟷ XNC via an efficient and economic perturbative wave function approach

ABSTRACT

The energetics, structures, reaction paths and mechanisms for the conversion XCN ⟷ XNC, with X = H, Li, CH₃ and H₂B have been investigated through the use of improved virtual orbitals (IVO) in a second-order multireference perturbation theory (MRPT) treatment within the framework of state-specific (SS) parametrisation of the wave function for the target state (IVO-SSMRPT). Due to its flexibility, IVO-SSMRPT formulation allows us to take into account the major part of the coupling between the dynamic and nondynamic correlation effects in an accurate manner. The results obtained by our calculations agree well with the state-of-the-art electronic structure methods and reference values which illustrates that IVO-SSMRPT, when applied judiciously, can be very accurate for reaction surfaces of XCN ⟷ XNC isomerisation, barrier and bond-parameters.

KEYWORDS:

• Multireference perturbation theory
• improved virtual orbitals
• state-specific method
• [1,2] sigmatropic shifts
• reaction pathways
• barrier height

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Authors gratefully acknowledge funding from the DST, India [grant number EMR/2015/000124]. S. Sinha Ray gratefully acknowledges financial support from UGC, India [Grant number 150586].