Absorption spectrum and absorption coefficients of NO₂ in the vacuum ultraviolet region

Abstract

The absorption coefficients of NO2 in the region from 500 to 1100 Å are measured by a photographic method using the radiation from electron synchrotron as a background source. For the Rydberg series due to the transition from 4a1 to npπ, parameters q and Γ in Mies equation are obtained and the parameter q is determined to be −0.4 for every member and Γ 4.808/n*3 eV where n* is the effective quantum number.The absorption spectrum of NO2 in the region from 600 to 1600 Å are also analyzed. New vibrational progressions that are observed around 950 Å, are assigned to the excitations from 4b2 to ns Rydberg states (n = 3, 4, and 5) converging to the 1B2 ionic state. Assignments and discussions of many other Rydberg series that appear in the absorption spectrum between 600 and 1600 Å are also presented.

The role of near-resonant intermediate states in the two-photon excitation of nitrogen dioxide: origin bands in bent-to-linear transitions

“…One of these states (12B1) is formally linear, all have N-O bond lengths longer than either the ground state (1.20 Á) or the 3p Rydbergs (1.09 Á). 10,12 With reference to the discussion of the previous Letter8 we see the prominence of a symmetric stretching progression together with the relatively flat Franck-Condon envelope in vf, as indicative of intramolecular relaxation at the intermediate level populated by absorption of the first photon.…”

The role of near-resonant intermediate states in the two-photon excitation of nitrogen dioxide: the distinct dynamics of two-photon photofragmentation

“…Photochem., 20, 175 (1982). (12) T. G. Slanger, W. K. Bischel, and M. J. Dyer, J. Chem. Phys., 79, 2231 (1983).…”

Ion Pair Formation in Multiphoton Excitation of NO2 Using Linearly and Circularly Polarized Femtosecond Light Pulses: Kinetic Energy Distribution and Fragment Recoil Anisotropy

“…The 12.52 eV (396 nm), quasi-resonant with the position of the 6p(ν 2 ) 2) state at 12.534 eV, lies at a minimum between the two resolved 5d(ν 2 ) 2,3) Rydberg states observed in the photoabsorption spectrum. 17 The measured KER max (V ) 0) ≈ 1.61 eV and the position of structures in the peaks assigned to the NO + (X 1 Σ + ,V ) 0-5) vibrational levels are consistent with the excitation of the 6p(ν 2 ) 2) state. Varying the photon wavelength on the 405-396 nm limited range might then induce excitation of R*[(4b 2 ) -1 ] Rydberg states of different C 2V symmetry; ns molecular orbitals (MO) have the a 1 symmetry character, np and nd MOs may involve all four a 1,2 and b 1,2 characters, although, for example, the nd MOs in the studied region had been assigned to an a 2 symmetry.…”

“…They are assigned to the ν 2 bending modes of the Rydberg members arising from the excitation of the 4b 2 molecular orbital in the NO 2 (X 2 A 1 ) ground state, converging to the NO 2 + (a 3 B 2 ) first electronically excited state of NO 2 + . [16][17][18] In this region, excitation of the R*[(4b 2 ) -1 ] series from the NO 2 (X 2 A 1 ) ground state, which has a bent geometry, is favored by Franck-Condon factors. The one-photon Ospectrum displays a sharp maximum characterized by a strong increase of the intensity for resonant excitation of two Rydberg states of this series at 12.4 and 12.47 eV, assigned to 4d (ν 2 ) 5,6) or 5d (ν 2 ) 1,2) Rydberg states, 26 in a region where the ionization cross section is slowly varying with energy.…”

“…Varying the photon wavelength on the 405-396 nm limited range might then induce excitation of R*[(4b 2 ) -1 ] Rydberg states of different C 2V symmetry; ns molecular orbitals (MO) have the a 1 symmetry character, np and nd MOs may involve all four a 1,2 and b 1,2 characters, although, for example, the nd MOs in the studied region had been assigned to an a 2 symmetry. 26 The width of the peaks in the KER spectra results from the convolution of the photon bandwidth with the intrinsic width of the NO 2 Rydberg states shown, for example, in the photoabsorption spectrum, 17 the unresolved contribution of neighboring Rydberg states, as well as from rotational excitation of the NO + fragment in the dissociation. Although the detailed structure analysis of the KER spectra suggests the role of different contributions, the spectra have been fitted by a single series of Gaussians in order to provide an overall quantitative estimate of the relative weight of the NO + (X 1 Σ + ,V) vibrational components.…”