Is there a potential minimum corresponding to singlet methylnitrene A study of the CH[sub 3]N to CH[sub 2]NH rearrangement on the lowest singlet state potential energy hypersurface

Journal Article · Sat Jan 01 00:00:00 EST 1994 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.466963· OSTI ID:5406204

Richards, C Jr; Meredith, C; Kim, S; Quelch, G E; Schaefer, III, H F ^[1]

---

1. Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602 (United States)

[ital Ab] [ital initio] molecular electronic structure methods have been used to examine the rearrangement of methylnitrene (CH[sub 3]N) to methyleneimine (CH[sub 2]NH) on the lowest-lying singlet surface. Geometries have been optimized and harmonic vibrational frequencies obtained for both methylnitrene and methyleneimine as well as for the transition states connecting them. Basis sets up to triple zeta plus double polarization plus [ital f] functions (TZ2P+[ital f] ) in size were used. Equilibrium geometries have been determined at the self-consistent field (SCF) and the single and double excitation configuration interaction (CISD) levels of theory. Because the [sup 1][ital E] state of CH[sub 3]N exhibits a Jahn--Teller splitting, the resulting [sup 1][ital A][prime] and [sup 1][ital A][double prime] states have been examined in order to determine their respective roles on the potential energy surface. After identifying and analyzing a larger [sup 1][ital A][prime]--[sup 1][ital A][double prime] splitting artifact due to symmetry breaking, the true classical Jahn--Teller splitting is predicted to be [lt]0.01 kcal mol[sup [minus]1]. This theoretical investigation is the first to consider the effects of electron correlation in conjunction with extended basis sets on the energetics of the methylnitrene 1,2-hydrogen shift. It is found that the conclusion of most previous lower level studies---that there is no barrier to rearrangement on the [sup 1][ital A][prime] surface---appears to be justified. If [ital C][sub [ital s]] symmetry is enforced, there is a sizable barrier ([similar to]30 kcal mol[sup [minus]1]) on the [sup 1][ital A][double prime] potential surface.

• DOE Contract Number: FG09-87ER13811
• OSTI ID: 5406204
• Journal Information: Journal of Chemical Physics; (United States), Vol. 100:1; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
METHYL RADICALS
POTENTIAL ENERGY
ORGANIC NITROGEN COMPOUNDS
CONFIGURATION INTERACTION
ELECTRON CORRELATION
ELECTRONIC STRUCTURE
EQUILIBRIUM
GEOMETRY
HARMONIC OSCILLATORS
OPTIMIZATION
ALKYL RADICALS
CORRELATIONS
ELECTRONIC EQUIPMENT
ENERGY
EQUIPMENT
MATHEMATICS
ORGANIC COMPOUNDS
OSCILLATORS
RADICALS
664100* - Theory of Electronic Structure of Atoms & Molecules- (1992-)