Anion photoelectron spectroscopy of B{sub 2}N{sup {minus}}
- Department of Chemistry, University of California, Berkeley
Vibrationally resolved 355 and 266 nm anion photoelectron spectra of B{sub 2}N are presented. Photodetachment to two electronic states of linear B{endash}N{endash}B is observed and, aided by electronic structure calculations, assigned to the {tilde X}&hthinsp;{sup 1}{Sigma}{sub g}{sup +}{r_arrow}{tilde X}&hthinsp;{sup 2}{Sigma}{sub u}{sup +}+e{sup {minus}} and {tilde X}&hthinsp;{sup 1}{Sigma}{sub g}{sup +}{r_arrow}{tilde A}&hthinsp;{sup 2}{Sigma}{sub g}{sup +}+e{sup {minus}} transitions. The electron affinity of B{sub 2}N is 3.098{plus_minus}0.005&hthinsp;eV and the {tilde A}&hthinsp;{sup 2}{Sigma}{sub g}{sup +} term energy T{sub 0} is 0.785{plus_minus}0.005&hthinsp;eV. Observation of excitations involving uneven quanta of the antisymmetric stretching mode (v{sub 3}) indicates a breakdown of the Franck{endash}Condon (FC) approximation and results from Herzberg{endash}Teller vibronic coupling between the {tilde X}&hthinsp;{sup 2}{Sigma}{sub u}{sup +} and {tilde A}&hthinsp;{sup 2}{Sigma}{sub g}{sup +} states involving the v{sub 3} mode. Measurement of the angular dependence of the photodetached electrons serves as a sensitive probe for the identification of these FC forbidden transitions. A linear vibronic coupling model qualitatively reproduces the perturbed v{sub 3} potentials of the {tilde X} and {tilde A} states. Artifactual symmetry breaking along the v{sub 3} coordinate is observed in the {ital ab initio} wave functions for the neutral ground state up to the coupled-cluster level of theory, even when Brueckner orbitals are used. No evidence is found for an energetically low-lying cyclic state of B{sub 2}N, which has been invoked in the assignment of the matrix infrared spectrum of B{sub 2}N. However, the matrix infrared data agrees well with the peak spacing observed in the photoelectron spectra and reassigned to the linear {tilde X}&hthinsp;{sup 2}{Sigma}{sub u}{sup +} ground state. {copyright} {ital 1999 American Institute of Physics.}
- OSTI ID:
- 692550
- Journal Information:
- Journal of Chemical Physics, Vol. 111, Issue 19; Other Information: PBD: Nov 1999
- Country of Publication:
- United States
- Language:
- English
Similar Records
Rotational-resolved pulsed field ionization photoelectron study of NO{sup +}(X {sup 1}{Sigma}{sup +},v{sup +}=0{endash}32) in the energy range of 9.24{endash}16.80 eV
High-resolution pulsed field ionization photoelectron-photoion coincidence spectroscopy using synchrotron radiation