scholarly journals Hyperfine Predissociation in Br2

1983 ◽  
Vol 1 (5) ◽  
pp. 185-193 ◽  
Author(s):  
J. B. Koffend ◽  
R. Bacis ◽  
S. Churassy ◽  
M. L. Gaillard ◽  
J. P. Pique ◽  
...  
Keyword(s):  
Hyperfine Structure ◽  
Nuclear Spin ◽  
Hyperfine Coupling ◽  
Spin Rotation ◽  
Coupling Constants ◽  
Hyperfine Coupling Constants ◽  
First Time

Hyperfine structure of several rovibronic transitions in the B-X system of B79r2 has been analyzed and the quadrupolar and nuclear spin rotation hyperfine coupling constants have been obtained. A strong hyperfine predissociation effect has been observed for the first time in Br2 and the related hyperfine and rotational parameters were determined in the B(0u+)ν′ = 11 level.

Rotational Spectra of 14N17O and 15N18O

1994 ◽  
Vol 49 (12) ◽  
pp. 1111-1118 ◽  
Author(s):  
Axel H. Saleck ◽  
Martin Liedtke ◽  
Alexandra Dolgner ◽  
Gisbert Winnewisser
Keyword(s):  
Hyperfine Coupling ◽  
Rotational Constant ◽  
Spin Rotation ◽  
Coupling Constants ◽  
Wave Spectra ◽  
Rotational Spectra ◽  
Yield Parameters ◽  
Oppenheimer Approximation ◽  
Data Yield ◽  
First Time

Abstract The mm-wave spectra of 15N18 O and 14N 17 O in both X2 Π1/2 and X2 Π3/2 states have been measured and assigned for the first time. Improved rotational and, for the first time, 17O hyperfine coupling constants have been derived from the analysis. The 14N17 O data yield parameters of the unpaired electron spatial distribution near both nuclei. Furthermore, the deviation from the Born-Oppenheimer approximation is confirmed on the basis of the rotational constants of five isotopomers. Finally, when comparing the nuclear spin-rotation constants to the ones of other molecules containing 14N or 17O nuclei, a roughly linear proportionality with the rotational constant B is found.

The lengthening of the HF bond on formation of heterodimers B • • • HF: determination and dependence on the strength of the hydrogen bond

1986 ◽  
Vol 404 (1826) ◽  
pp. 89-99 ◽  
Keyword(s):  
Hydrogen Bond ◽  
Nuclear Spin ◽  
Hyperfine Coupling ◽  
Coupling Constants ◽  
Rotational Spectra ◽  
Bond Stretching ◽  
Monotonically Increasing Function ◽  
First Time ◽  
Increasing Function

We report a procedure that for the first time allows the quantitative determination of the lengthening δr of the HF bond on formation of an isolated hydrogen-bonded dimer B···HF. We show how δr can be obtained from the ground-state hyperfine coupling constants X (D nuclear quadrupole) and D HF (H, F nuclear spin to nuclear spin), which are available from the rotational spectra of the molecules B···H(D)F. We establish the values of δr for the series of heterodimers B···HF where B = Ar, Kr, Xe, N 2 , CO, H 2 S, HCN, CH 3 CN and H 2 O. The values of δr are zero for the first three members of this series and then 0.001, 0.007, 0.010, 0.014, 0.016 and 0.015 Å, respectively (1 Å = 10 -1 nm = 10 -10 m). It is found that δr is a monotonically increasing function of the hydrogen-bond stretching force constant k σ , which is taken as a convenient measure of the hydrogen bond strength.

Spectroscopiċ investigations of hydrogen bonding interactions in the gas phase. X. Properties of the hydrogen-bonded heterodimer HCN∙ ∙ ∙HF determined from hyperfine coupling and centrifugal distortion effects in its ground-state rotational spectrum

1985 ◽  
Vol 401 (1821) ◽  
pp. 327-347 ◽  
Keyword(s):  
Nuclear Spin ◽  
Hyperfine Coupling ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Hyperfine Coupling Constants ◽  
Rotational Spectra ◽  
Isotopic Species ◽  
Centrifugal Distortion Constants

The rotational spectra of six isotopic species of HCN∙ ∙ ∙HF in their vibrational ground states have been observed by pulsed-nozzle, Fourier-transform, microwave spectroscopy and have been analysed to yield the rotational constants B 0 , centrifugal distortion constants D J and various hyperfine coupling constants X i (D), X 3 ( 14 N) and D 4, 5 as follows (subscripts refer to the numbering scheme H (1) C (2) N (3) ∙ ∙ ∙H (4) F (5) ). isotopic species B 0 / MH Z D J /kH Z X i (D)/kH Z X 3 ( 14 N)/MH Z D 4, 5 (H, F)/kH Z HC 15 N∙ ∙ ∙HF 3573 5874(2) 6.97(2) ─ ─ –242(6) HC 15 N∙ ∙ ∙DF 3551.5110 6.83 269(4)( i = 4) ─ ─ HC 14 N∙ ∙ ∙HF 3591.1552 6.99 ─ –4.098(4) –218(6) HC 14 N∙ ∙ ∙DF 3569.6576 6.86 259(2)( i = 4) –4.096(1) ─ DC 15 N∙ ∙ ∙HF 3360.3549 5.85 186(5)( i = 1) ─ –244(4) DC 15 N∙ ∙ ∙DF 3338.0824 5.81 { 181(10) ( i = 1) ─ ─ 283(7) ( i = 4) The B 0 values lead to conclusions about the dimer geometry, the D J values allow the hydrogen bond stretching force constant k σ to be determined and the hyperfine coupling constants provide information about the internal dynamics of the subunits. An analysis of the D nuclear quadrupole coupling and H, F nuclear spin nuclear-spin coupling constants demonstrates that the H—F bond lengthens by 0.14 Å when the heterodimer HCN∙ ∙ ∙HF is formed. (1 Å = 10 –10 m = 10 –1 nm.)

HYPERFINE COUPLING CONSTANTS OF FLUORINATED BENZENE RADICAL CATIONS: A DFT B3LYP AND MP2 STUDY

2008 ◽  
Vol 07 (04) ◽  
pp. 879-887 ◽  
Author(s):  
HONG-YAN XIAO ◽  
YA-JUN LIU ◽  
WEI-HAI FANG ◽  
RUO-ZHUANG LIU ◽  
MASARU SHIOTANI
Keyword(s):  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Hyperfine Coupling ◽  
Radical Cations ◽  
Coupling Constants ◽  
Epr Spectra ◽  
Hyperfine Coupling Constants ◽  
First Time ◽  
Hyperfine Structures

The EPR spectra of a series of fluorinated benzene radical cations were first-time assigned by MP2//B3LYP quantum chemical calculations. Most of the calculated values are in agreement with the experimentally observed ones. The hyperfine structures of some cations with near-degenerated states were well assigned with the help of extra QCISD calculations.

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