Theoretical study of the photoelectron spectrum of NO3 and the excited states of NO3+. I. Electronic spectrum

Abstract

Articles you may be interested inThe electronic states of 1,2,4-triazoles: A study of 1H-and 1-methyl-1,2,4-triazole by vacuum ultraviolet photoabsorption and ultraviolet photoelectron spectroscopy and a comparison with ab initio configuration interaction computationsThe photoelectron spectroscopy of NO 3 is of considerable interest, particularly because of the radical's relevance in atmospheric chemistry, but recent studies gave controversial results. In the current study we present high-level ab initio calculations of the vertical and adiabatic electronic spectrum of NO 3 ϩ and the photoelectron spectrum of the radical. The vertical ionization spectrum up to 18 eV was calculated by complete active space self-consistent field and multireference configuration interaction methods, using extended basis sets. For D 3h geometries 15 ionic singlet and triplet states are found and characterized within this energy range, of which only the lowest four are due to principal ionization. For geometries of lower symmetry these states split into 23 states, of which seven correspond to principal ionizations. Equilibrium geometries and harmonic frequencies were computed for the controversial higher principal ionizations, and adiabatic ionization potentials were obtained. These results disagree in several points with previous experiments and their interpretation, which is discussed in detail.

Ab initio calculation of electronic absorption spectra and ionization potentials of C3H3 radicals

“…This was shown in previous studies by comparison of calculated and experimentally well-known 0-0 transitions. [50][51][52] Thus, it is likely that the radical undergoes a strong geometry change upon excitation into this state which may be associated with rather complex vibrational dynamics. Indeed, in the early computational study by Honjou et al a structure of C s symmetry was optimized which is significantly distorted.…”

Theoretical study of the photodetachment spectrum of the methylene amidogene anion (H2CN−)

“…Thus, here a different method is devised which makes use of the structure of the MRCI wave functions of initial and final states. 33 The partial-channel ionization cross section s f,q for ionization out of a single orbital q and resulting in final state |c NÀ1 f i can be approximated by…”