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Journal ArticleDOI

The 2B1 ← 2A1 system of nitrogen dioxide☆

01 Sep 1973-Chemical Physics Letters (North-Holland)-Vol. 21, Iss: 3, pp 458-461
TL;DR: The vibrational structure of the 2B1 ← 2A1 system of NO2 has been assigned to a progression in ν′2. as mentioned in this paper showed that the bending potential function is expressed as a rapidly converging Taylor series expansion about the linear configuration.
About: This article is published in Chemical Physics Letters.The article was published on 1973-09-01. It has received 100 citations till now.
Citations
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Journal Article
TL;DR: Theorie des effets de couplage vibronique multimodes is described in this paper, where couplages mettant en jeu des modes and des etats degeneres.
Abstract: Mise au point. Theorie des effets de couplage vibronique multimodes. Probleme a 2 etats. Couplage vibronique mettant en jeu des modes et des etats degeneres. Effets du couplage vibronique multimodes en spectroscopie. Comportement statistique des niveaux d'energie vibroniques. Intersections coniques et evolution temporelle de la fluorescence

1,424 citations

Journal ArticleDOI
TL;DR: In this article, a multiconfiguration self-consistent field (MC-SCF) wavefunctions have been computed for the low-lying X 2A1, A 2B2, B 2B1, C 2A2, 4B2 and 2Σ+g electronic states of NO2.
Abstract: Traditional spectroscopic analysis of the complex and irregular absorption spectrum of NO2 has provided a relatively small amount of information concerning the nature of the excited states. An extensive ab initio investigation has been undertaken, therefore, to provide a basis for interpretation of the experimental results. Multiconfiguration self‐consistent‐field (MC–SCF) wavefunctions have been computed for the low‐lying X 2A1, A 2B2, B 2B1, C 2A2, 4B2, 4A2, and 2Σ+g electronic states of NO2. The minima of the A 2B2, B 2B1, and C 2A2 states have all been found to be within 2 eV of the minimum of the X 2A1 ground state; for these states, C2v potential surfaces have been constructed for purposes of a spectral interpretation. The 4B2, 4A2, and 2Σ+g states are all more than 4 eV above the minimum of the ground state and have been examined in less detail. The study described here significantly improves on previous NO2 ab initio calculations in three important areas: (1) The double‐zeta‐plus‐polarization quality basis set is larger and more flexible; (2) the treatment of molecular correlation is more extensive; and (3) the electronic energies have been calculated for several different bond lengths and bond angles in each state. For the four lowest doublet states the following spectral data have been obtained: The ground state experimental constants are included in parentheses. The estimated accuracy of the various parameters is ±0.02 A for bond length, ±2° for bond angle, ±10% for the vibrational frequencies, ±0.10 D for dipole moments, and ±0.3 eV for the adiabatic excitation energies. An unusual feature has been found for the 2Σ+g state. The equilibrium geometry of this linear state has two unequal bond lengths of 1.20 A and 1.42 A and the inversion barrier is approximately 800 cm−1.

253 citations

Journal ArticleDOI
TL;DR: In this article, the laser induced dispersed fluorescence spectra (L.I.D.F.S) of jet cooled NO2 molecules in emission from 11 different vibronic levels located between 22.006 and 23.625 cm−1 was recorded.
Abstract: The laser induced dispersed fluorescence spectra (L.I.D.F.S.) of jet cooled NO2 molecules in emission from 11 different vibronic levels located between 22 006 and 23 625 cm−1 was recorded. The corresponding variety of Franck–Condon accesses has allowed the observation of the complete set of the 191 lowest vibrational levels of the X 2A1 ground state, located up to 10 000 cm−1. The vibrational band origins were measured to within typically 0.3 cm−1, assigned (n1, n2, n3), and fitted with a 24 coefficient Dunham expansion giving a typical residual error of 0.5 cm−1. Furthermore, the vibrationless A 2B2 level has probably also been observed at 9737 cm−1. A perturbative model of the X 2A1–A 2B2 vibronic interaction has been used in order to calculate the energy shift of the high vibrational levels (around 10 000 cm−1) of the X 2A1 state.

154 citations

Journal ArticleDOI
TL;DR: In this paper, the shape of the potential energy surface of a triatomic molecule over a wide range of values for the bending coordinate is determined by numerical integration of the wave equation in order to relate the shape to the rotation-bending energies.

139 citations

References
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Journal ArticleDOI
TL;DR: In this article, a method for determining the position of an atom in a molecule from spectroscopic measurements on two isotopic species of the molecule is described, and explicit expressions are derived for linear, symmetric top, planar, and nonplanar asymmetric top molecules.
Abstract: A method is described for determining the position of an atom in a molecule from spectroscopic measurements on two isotopic species of the molecule. The method is applied to various types of molecules; explicit expressions are derived for linear, symmetric top, planar, and nonplanar asymmetric top molecules. The number of isotopic species on which measurements must be made to complete the structural determination, i.e., determine the position of every atom in the molecule, is discussed for various types of molecules. An application of the method to the determination of mass difference ratios is also considered.

1,397 citations

Journal ArticleDOI
TL;DR: The results obtained for 14N16O2 are: Rotational constantsA=239 868.7±11 Mc/secB= 13 000.12±0.6 Mc/ secC= 12 303.45±0 6.6Mc/secOdd electron expectation values with respect to (3ra2−1)/2r3〉=−1.73×1024cm−3N−nucleus〈(rb−irc)2/r3
Abstract: Some 69 microwave absorption lines from three isotopic modifications of NO2 have been observed and identified. This spectrum has been completely analyzed in terms of moments of inertia, magnetic fine structure, and centrifugal distortion. The early stages of analysis were complicated by the existence of many mathematical solutions satisfying all of the data then available, but special methods have been developed for treating limited data and selecting the one solution giving the true molecular parameters.The results obtained for 14N16O2 are: Rotational constantsA=239 868.7±11 Mc/secB= 13 000.12±0.6 Mc/secC= 12 303.45±0.6 Mc/secOdd electron expectation values with respect to〈(3ra2−1)/2r3〉=−1.73×1024cm−3N−nucleus〈(rb−irc)2/r3〉=+3.34×1024cm−3|ψ(0)|2=+3.065×1024cm−3Reduced spin−rotation coupling constantseaa/A=+0.022563ebb/B=+0.000608ecc/C=−0.007764Force constants from combined microwave−infrared datafd=11.043±0.05 mydn/Afα= 1.109±0.01fdd=0.481±0.014fdα=2.140±0.05. The magnetic coupling constants are disc...

188 citations

Journal ArticleDOI
TL;DR: In this article, an investigation of the absorption spectra of both 14NO2 and 15NO2 has revealed a long progression of red-degraded bands in the region 3 700 −4 600 A.
Abstract: An investigation of the absorption spectra of both 14NO2 and 15NO2 has revealed a long progression of red-degraded bands in the region 3 700–4 600 A. The rotational analysis shows that these bands ...

181 citations

Journal ArticleDOI
TL;DR: In this article, the excitation energies, potential energy surfaces, and oscillator strengths computed in the previous paper are discussed in light of experimentally reported spectroscopic data, namely absorption, fluorescence, chemiluminescence, predissociation, photolysis, and the absence of phosphorescence.
Abstract: The excitation energies, potential‐energy surfaces, and oscillator strengths computed in the previous paper are discussed in light of experimentally reported spectroscopic data, namely absorption, fluorescence, chemiluminescence, predissociation, photolysis, and the absence of phosphorescence. It is found that the main components of the visible spectrum are due to the transitions 2B1 ← 2A1, and 2B2 ← 2A1, with the 2B2 state being responsible for the observed fluorescence emission. The anomalous fluorescence lifetime is also discussed.

51 citations