Spin-rotation interactions in the nuclear spin conversion of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">CH</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mi mathvariant="normal">F</mml:mi></mml:math>

Ilisca, E.; Bahloul, K.

doi:10.1103/physreva.57.4296

Cited by 26 publications

(36 citation statements)

References 11 publications

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“…Solution for the latter can be found in [22,20,23], which allows to express the strength of mixing in formaldehyde bŷ…”

Section: Mixing Of the Ortho And Para Statesmentioning

confidence: 99%

Nuclear spin conversion in formaldehyde

Chapovsky¹

2001

Journal of Molecular Structure

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Theoretical model of the nuclear spin conversion in formaldehyde (H 2 CO) has been developed. The conversion is governed by the intramolecular spinrotation mixing of molecular ortho and para states. The rate of conversion has been found equal γ/P = 1.4 · 10 −4 s −1 /Torr. Temperature dependence of the spin conversion has been predicted to be weak in the wide temperature range T = 200 − 900 K.

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“…Solution for the latter can be found in [22,20,23], which allows to express the strength of mixing in formaldehyde bŷ…”

Section: Mixing Of the Ortho And Para Statesmentioning

confidence: 99%

Nuclear spin conversion in formaldehyde

Chapovsky¹

2001

Journal of Molecular Structure

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“…These perturbations originate from the nuclear spin-spin, or spin-rotation interactions [8][9][10][11].…”

Section: Rate Equationsmentioning

confidence: 99%

Coherent control of nuclear spin isomers of molecules: the role of molecular motion

Chapovsky

2002

Molecular Physics

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“…In addition, for the first time, the ( k = ±1) matrix elements diagonal in I T were treated, as well as those with ( k = ±1, ±2) off-diagonal in I T . In connection with the light-induced drift experiments on CH 3 F, the full set of ( k = ±1, ±2) spin-rotation matrix elements was developed in 1995 by Gus'kov [21] using the low-field representation, and in 1998 by Ilisca and Bahloul [22] for the high-field case. In the current work, the ( k = ±1, ±2) matrix elements of H SR diagonal in I T required for analysis of the microwave spectrum of NSF 3 in the excited degenerate vibrational state v 5 = 1 will be derived for RV = E in the low-field representation.…”

Section: Introductionmentioning

confidence: 99%

Anomalous hyperfine structure of NSF3in the degenerate vibrational statev5=1: Lifting of the parity degeneracy by the

et al. 2010

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For the principal isotopologue 14 N 32 S 19 F 3 of thiazyl trifluoride in the degenerate fundamental state (v 5 = 1), the hyperfine structure has been investigated in the Q-branch spectrum between 8 and 26.5 GHz using microwave Fourier transform waveguide spectrometers with a resolution limit of ≈30 kHz. In addition to l-type doubling spectra and l-type resonance transitions with ( k = l = ±2), perturbation-allowed spectra were measured with (k − l) = ±3, ±6. The range in J was from 13 to 61; for the lower states, kl = −3, −2, −1, 0, +1. For all the transitions, the hyperfine patterns observed are predicted to be doublets when only the nitrogen quadrupole Hamiltonian H N Q is taken into account. Doublets were indeed measured for transitions with RV = A 1 ↔ A 2 , where RV is the rovibrational symmetry. However, when RV = E ↔ E, triplets and quartets were observed in addition to doublets. These anomalous hyperfine patterns are shown to be due to the ( k = ±1) and ( k = ±2) matrix elements of the fluorine spin-rotation Hamiltonian H F SR characterized by the fluorine spin-rotation constants c(1) = 1 2 (c xz + c * zx ) and c(2) = 1 2 (c xx − c yy ), respectively. These terms in H F SR lift the parity degeneracy for RV = E. The rovibrational Hamiltonian H RV was adopted from an earlier partner study [S. Macholl et al., J. Phys. Chem. A 113, 668 (2009)]. A good fit to the hyperfine data was obtained with a standard deviation of 3.1 kHz. In the fitting process, 12 rovibrational parameters were varied, while the remaining constants in H RV were left at the values of Macholl et al. In addition, six hyperfine parameters were determined: four in H N Q , and two in H F SR . It was found that |c(1)| = 7.48(24) kHz and |c(2)| = 2.423 (22) kHz. This determination of c(1) is the first to be reported based on frequency measurements. In all the previous detections of parity doubling where the splittings were accounted for quantitatively, the levels involved had K = |k| = 1 in studies of the ground vibrational state or G ≡ |k − l| = 1 in investigations of degenerate vibrational states. In the current work, several different values of G were involved, thus demonstrating experimentally for the first time that this splitting process is a general phenomenon. The key to the observation of the parity doubling lies in the regional resonances discovered by Macholl et al. The clustering of rovibrational levels at low K leads to severe mixing. For each eigenstate involved in a regional resonance, the eigenstate consists of a linear superposition of basis vectors with several different values of kl having sizable expansion coefficients. As a result, the ( k = ±1, ±2) matrix elements of H F SR that typically connect levels widely separated in energy occur here effectively on the diagonal, thereby greatly enhancing the effects of c(1) and c(2). These spin-rotation matrix elements are derived here for RV = E in the low-field representation.

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Spin-rotation interactions in the nuclear spin conversion ofCH3F

Cited by 26 publications

References 11 publications

Nuclear spin conversion in formaldehyde

Nuclear spin conversion in formaldehyde

Coherent control of nuclear spin isomers of molecules: the role of molecular motion

Anomalous hyperfine structure of NSF3in the degenerate vibrational statev5=1: Lifting of the parity degeneracy by the

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