Electron spin resonance and theoretical studies of the 14 N....14N and 15N....15N spin-pair radicals in neon matrices: The effects of mixing among the 1Σ+g, 3Σ+u, 5Σ+g, and 7Σ+u electronic states
ACS Citation
Knight, L. B.; Bell, B. A.; Cobranchi, D. P.; Davidson, E. R.; Electron spin resonance and theoretical studies of the 14 N....14N and 15N....15N spin-pair radicals in neon matrices: The effects of mixing among the 1Σ+g, 3Σ+u, 5Σ+g, and 7Σ+u electronic states J. Chem. Phys. 1999, 111, 3145-3145.
Version of Record
Abstract
The first experimental and theoretical study of the N⋅⋅⋅⋅N spin-pair radical is reported. Its high-resolution ESR (electron spin resonance) spectrum has been observed in neon matrices and interpreted on the basis of weakly interacting atoms using a model recently developed for the H⋅⋅⋅⋅H spin-pair. To fully interpret the N⋅⋅⋅⋅N radical results it was necessary to include electronic state mixing effects among all possible spin states, namely the 1Σ+g, 3Σ+u, 5Σ+g, and 7Σ+u states. Several different trapping sites were observed which indicated the interaction of N atoms at distinctly different separation distances in the neon lattice. Calculated J values at the complete active space self-consistent field (CASSCF) level (TZP basis set) were compared with the experimental results for the various trapping site distances. The 15N⋅⋅⋅⋅15N radical in the dominant trapping site had magnetic parameters of g=2.0016(2), A(15N)=15.9(1) MHz, D=−178(1)MHz and J=468(2) MHz. Using the point dipole approximation this corresponds to a N⋅⋅⋅⋅N separation distance of 6.41 Å. A most unusual type of magnetic dipole transition was observed that involves a transition between electronic states of formally different S values where S is the total spin quantum number for a given electronic state.
Source Name
Journal of Chemical Physics
Publication Date
1-1-1999
Volume
111
Issue
7
Page(s)
4587-4587
Document Type
Citation
Citation Type
Article