The 2491 Å band system of NO2. Rotational structure and evidence for predissociation in the zero-point level

1976 ◽  
Vol 54 (11) ◽  
pp. 1157-1171 ◽  
Author(s):  
K. -E. J. Hallin ◽  
A. J. Merer
Keyword(s):  
Vibrational Level ◽  
Band System ◽  
Zero Point ◽  
Spin Rotation ◽  
Rotational Analysis ◽  
Coupling Constant ◽  
Centrifugal Distortion ◽  
Minimum Potential ◽  
Centrifugal Distortion Constants ◽  
Point Level

A detailed rotational analysis of the (0, 0) band of the [Formula: see text] electronic transition of NO2, at 2491 Å, has been carried out. Although the lines are slightly broadened as a result of predissociation, it has been possible to determine the five quartic centrifugal distortion constants and the spin–rotation coupling constant εaa for the upper state. The centrifugal distortion constants allow the position of the unseen vibrational level ν3′ to be estimated: the results offer no support to the suggestion of Coon, Cesani, and Huberman that there is a double minimum potential function in the antisymmetric stretching coordinate of the 2B2 state. The geometric structure of the zero-point level of the 2B2 state is r(N—O) = 1.3142 Å, [Formula: see text], and its lifetime (as calculated from the linewidths) is 42 ± 5 ps.

The microwave spectrum of the ClS2 free radical

1994 ◽  
Vol 72 (11-12) ◽  
pp. 1043-1050 ◽  
Author(s):  
Masaharu Fujitake ◽  
Eizi Hirota
Keyword(s):  
Free Radical ◽  
Force Field ◽  
Electronic Spectroscopy ◽  
Spin Rotation ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Harmonic Force ◽  
Isotopic Species ◽  
Spin Resonance ◽  
Centrifugal Distortion Constants

The rotational spectrum of the ClS2 free radical in the gaseous phase has been observed in the millimetre- and submillimetre-wave regions. The ClS2 radical was generated by a dc glow discharge in either S2Cl2 or SCl2. Both a- and b-type R-branch transitions, most of which were split into two fine structure components, were detected for both of the 35Cl and 37Cl isotopic species in the ground vibronic state. As expected from the small hyperfine interaction constants reported by an electron spin resonance (ESR) study, the hyperfine structure was resolved for none of the transitions observed in the present study. Analysis of the observed transition frequencies yielded rotational and centrifugal distortion constants and also spin–rotation interaction constants with their centrifugal corrections. The spin–rotation interaction constants obtained in the present study were consistent with g values of the ESR study. The rotational constants of the two isotopic species led to the structure parameters r(S—S) = 1.906 (7) Å, r(S—Cl) = 2.071 (5) Å, and θ(SSCl) = 110.3 (4)°. A harmonic force field was derived from the observed centrifugal distortion constants and inertial defects combined with the ν1 frequency reported in literature on electronic spectroscopy. This harmonic force field yielded the ν2 and ν3 frequencies (445 (21) and 213.0 (2) cm−1, respectively, for 35ClS2), which differed considerably from the values reported previously.

Rotational Spectrum of Aminoborane: Centrifugal Distortion Constants and Boron and Nitrogen Hyperfine Structure

1991 ◽  
Vol 46 (9) ◽  
pp. 770-776 ◽  
Author(s):  
Kirsten Vormann ◽  
Helmut Dreizler ◽  
Jens Doose ◽  
Antonio Guarnieri
Keyword(s):  
Hyperfine Structure ◽  
Spin Rotation ◽  
Coupling Constants ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Rotational Spectra ◽  
Quadrupole Coupling ◽  
Wave Region ◽  
Nuclear Quadrupole ◽  
Centrifugal Distortion Constants

AbstractThe boron and nitrogen hyperfine structure in the rotational spectra of two aminoborane isotopomers, 11 BH2NH2 and 10BH2NH2, has been investigated and the quadrupole coupling constants of boron 10B, 11B and nitrogen 14N have been determined. We get the following results for the nuclear quadrupole coupling constants: χaa(11B) = -1.684 (14) MHz, χbb(11B) = -2.212 (11) MHz, χcc(11B) = 3.896(11) MHz, χaa(10B) = -3.481 (11) MHz, χbb(10B) = -4.623 (14) MHz, χCC(10B) = 8.104 (14) MHz and xaa(14N) = 0.095 (9) MHz, χbb(14N) = 2.091 (8) MHz, χcf4 (14N)=-2.186 (8) MHz. These nitrogen quadrupole coupling constants are those of the 11BH2 NH2 isotopomer. Additionally we were able to determine two out of the three spin rotation coupling constants caa, cbb, and ccc of boron, caa(11 B = 55.2 (26) kHz, cbb(11B) = 6.62 (36) kHz, caa (10B) = 15.26 (69) kHz and cbb(10B) = 4.94 (70) kHz. The spin rotation coupling constants ccc had to be fixed to zero in both cases. Furthermore we measured the rotational spectra in the mm-wave region to determine all quartic and several sextic centrifugal distortion constants according to Watson's A and S reduction

Millimetre-wave spectrum of HC17O+. Experimental and theoretical determination of the quadrupole coupling constant of the 17O nucleus

2001 ◽  
Vol 79 (2-3) ◽  
pp. 359-366 ◽  
Author(s):  
L Dore ◽  
C Puzzarini ◽  
G Cazzoli
Keyword(s):  
Wave Spectrum ◽  
Quadrupole Coupling Constant ◽  
Basis Sets ◽  
Coupling Constant ◽  
Centrifugal Distortion ◽  
Millimetre Wave ◽  
Quadrupole Coupling ◽  
Self Consistent Field ◽  
Centrifugal Distortion Constants

The millimetre-wave spectrum of HC17O+ has been analyzed up to 348.2 GHz by recording the J = 2 [Formula: see text] 1 and J = 4 [Formula: see text] 3 rotational transitions. Present measurements and the previous detection of the J = 1 [Formula: see text] 0 transition carried out in this laboratory allowed us to determine accurate values of the rotational and centrifugal distortion constants, and of the nuclear quadrupole coupling (χ) and spin-rotation constants. Moreover, χ has been evaluated from the electric field gradient at the oxygen nucleus calculated by using the multiconfiguration self-consistent field approach plus subsequent multireference configuration interaction computation, employing basis sets of quadruple zeta quality. Excellent agreement with experiment has been obtained. In addition, the molecular dipole moment has been calculated at the same level of accuracy. PACS No.: 33.20Bx

Laser-induced fluorescence of MnS: rotational analysis of the A6Σ+ – X6Σ+ transition

1985 ◽  
Vol 63 (11) ◽  
pp. 1380-1388 ◽  
Author(s):  
M. Douay ◽  
B. Pinchemel ◽  
C. Dufour
Keyword(s):  
Laser Excitation ◽  
Band System ◽  
Single Mode ◽  
Laser Induced Fluorescence ◽  
Spin Rotation ◽  
Spin Interaction ◽  
Rotational Analysis ◽  
Excitation Spectra ◽  
High Resolution Spectrometer ◽  
Resolution Spectrometer

Laser-excitation spectra of the rotational structure of the A6Σ+ – X6Σ+ transition of MnS has been performed. The combination of a single-mode dye laser and a high-resolution spectrometer have allowed analysis of a very congested spectrum in which the spin–rotation interaction completely dominates the spin–spin interaction. The (0,1) and (0,3) bands have been analyzed from laser-excitation spectra, and some information has been extracted from the emission spectrum of the (0,0) band. In addition, observation of a second band system confirms results already published by Monjazeb and Mohan.

Rotational analysis of the 6480 Å absorption of NO2

1979 ◽  
Vol 57 (3) ◽  
pp. 428-441 ◽  
Author(s):  
J. C. D. Brand ◽  
K. J. Cross ◽  
A. R. Hoy
Keyword(s):  
Vibrational Level ◽  
Vibronic Coupling ◽  
Spin Splitting ◽  
Order Effects ◽  
Centrifugal Distortion ◽  
Vibronic Band ◽  
Visible Absorption ◽  
Centrifugal Distortion Constants ◽  
Franck Condon ◽  
Higher Order Effects

About 300 rotational transitions in the 6480 Å region in the visible absorption of NO2 gas have been assigned by laser-excited fluorescence. A majority of the stronger transitions belong to the K = 0 and K = 1 subbands of a vibronic band, T0 = 15 434.9 cm−1, whose upper state is predominantly an a1, vibrational level of the electronic 2B2 basis state. Other groups of relatively weaker lines form (i) a severely-perturbed K = 2 subband attributed to the same series as the K = 0 and 1 subbands; (ii) a well-developed though relatively weak K = 3 subband assigned to a hybrid level of mainly 2A1, character, the transition to this level being induced by vibronic coupling; and (iii) a K = 6 subband assigned to a parent (i.e., 2B2 basis) vibrational level different from that identified at 15 435 cm−1. The spectrum in this region abundantly illustrates the irregularities, 'extra' lines, resonance crossings, and erratic spin splitting now recognized as widespread in the NO2 visible absorption. Rotational constants are not well defined and vary considerably from one subband to another: large pseudo-centrifugal distortion constants are attributed to higher-order effects of the vibronic coupling. Franck–Condon analysis of the intensity distribution in fluorescence leads to a tentative vibrational assignment of 1 60 for the stale at 15 435 cm−1.

Microwave spectrum and molecular structure of the HS2 radical

1994 ◽  
Vol 72 (11-12) ◽  
pp. 954-962 ◽  
Author(s):  
Satoshi Yamamoto ◽  
Shuji Saito
Keyword(s):  
Zero Point ◽  
Force Constants ◽  
Spectral Lines ◽  
Centrifugal Distortion ◽  
Harmonic Force ◽  
Rotational Constants ◽  
Anharmonic Constants ◽  
Microwave Spectrometer ◽  
Centrifugal Distortion Constants ◽  
Space Cell

Rotational spectral lines of the HS2 and DS2 radicals in the 2A″ ground electronic state are detected by a source-modulation microwave spectrometer combined with a free-space cell. The HS2 radical is produced in the cell by discharging a pure H2S gas. The spectrum of DS2 is observed by using a mixture of H2S and D2. The rotational constants, the centrifugal distortion constants, the spin-rotation interaction constants with their centrifugal distortion corrections, and the hyperfine interaction constants for the hydrogen nucleus are determined by least-squares analyses. The harmonic force constants are evaluated from the observed centrifugal distortion constants in combination with the vibrational frequencies reported previously. The zero-point average structure of HS2 is determined from the observed rotational constants of HS2 and DS2 with the aid of the harmonic force constants: rz(S—S) = 1.9650 (7) Å, rz (S—H) = 1.362 (3) Å, and αz (HSS) = 101/7 (4)° (1 Å = 10−10 m). The equilibrium distances for the S—S and S—H bonds are derived to be 1.9606 (7) Å and 1.352 (3) Å, respectively, by assuming the anharmonic constants of the corresponding diatomic molecules.

Bromine Spin-Rotation Coupling Constants of Cyclopropylbromide-79Br and -81Br

1992 ◽  
Vol 47 (3) ◽  
pp. 507-510
Author(s):  
N. Heineking ◽  
J. Gripp ◽  
H Dreizler
Keyword(s):  
Fourier Transform ◽  
Fourier Transform Spectroscopy ◽  
Microwave Spectrum ◽  
Spin Rotation ◽  
Coupling Constants ◽  
Centrifugal Distortion ◽  
Rotational Constants ◽  
Diagonal Component ◽  
Quadrupole Coupling ◽  
Centrifugal Distortion Constants

AbstractWe reinvestigated the microwave spectrum of cyclopropylbromide with the increased resolution of pulsed microwave Fourier transform spectroscopy. Because of the higher frequency precision, it was possible to determine the spin-rotation coupling constants of bromine. Global fits of rotational constants, quartic centrifugal distortion constants, quadrupole coupling constants including the off-diagonal component χac , and spin-rotation coupling constants simultaneously to almost one hundred hyperfine components for each of the two bromine isotopomers resulted in overall standard deviations of well below 5 kHz

scholarly journals The Microwave Q-branch Spectrum of Germane in the Vibrational Ground State

1986 ◽  
Vol 41 (5) ◽  
pp. 747-751 ◽  
Author(s):  
W. Stahl ◽  
H. Dreizler ◽  
L. Jörissen ◽  
W. A. Kreiner
Keyword(s):  
Fourier Transform ◽  
Ground State ◽  
Spin Rotation ◽  
Subsequent Paper ◽  
Centrifugal Distortion ◽  
Rotational Spectra ◽  
Vibrational Ground State ◽  
Spin Interactions ◽  
Centrifugal Distortion Constants

We present an analysis of the rotational spectra of 70GeH4, 72GeH4 and 74GeH4 in the vibrational ground state measured by microwave Fourier transform (MWFT) spectroscopy. All quartic, sextic and octic tensor centrifugal distortion constants have been determined. A discussion of spin-rotation and spin-spin interactions will be given in a subsequent paper.

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