Intensities of hyperfine components in saturation spectroscopy

Bordé, J.; Bordé, Ch. J.

doi:10.1016/0022-2852(79)90063-8

Cited by 54 publications

(16 citation statements)

References 10 publications

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“…This means that the absorbed EM field modifies the population of the lower and upper levels by pumping but is not itself altered by the absorption process. This calculation deviates from perturbative approaches commonly used to calculate the third-order susceptibility tensor when a pump and a probe beam can be distinguished [46][47][48]. Here, the role of both interfering EM fields is permutable (both pump and probe beams are identical), which gives a high symmetry to the problem.…”

Section: Introductionmentioning

confidence: 73%

Saturated absorption and crossover resonances in a high-finesse cavity: Formalism and application to the hyperfine structure of jet-cooled NO2by saturated-absorption cavity-ring-down spectroscopy

Dupré

2012

Phys. Rev. A

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The q R 0 (0) rotational transition in the A 2 B 2 ←− X 2 A 1 system of jet-cooled NO 2 located around 12 536 cm −1 is analyzed using a nonlinear-susceptibility formalism designed to describe the saturated absorption due to two identical counter-propagating radiations in an n-level system. An analytical solution of the equations of motion is obtained in the frequency space by considering the pertinent experimental conditions, mainly a high-finesse cavity and a slit-shaped supersonic expansion. Calculation of the nonlinear absorption coefficient requires the summing of all Zeeman-component contributions and a final numerical integration over the frequency detuning assuming a Maxwell-Boltzmann speed distribution. Determination of the experimental absorption coefficients is obtained by converting the shape of the temporal decay of the electromagnetic field amplitude initially captured inside the cavity. The molecular Hamiltonian includes both spin-rotation and hyperfine interactions. Molecular constants relative to the upper level are derived by exploiting Doppler-broadening-free so-called saturated-absorption cavity-ring-down spectroscopy. The dipole moment of the partially assigned hot band is obtained [μ band = 0.0047(12) D] together with the number density and the effective population relaxation rates. The model is validated by varying the intracavity power from 0 to 230 W (i.e., up to a maximum peak irradiance of 240 × 10 3 W/cm 2 ), representing saturation coefficients up to 120. The experimental position, shape, and width of the Lamb and crossover dips are well reproduced. The spatial shape and modulation of the electromagnetic field are discussed.

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Section: Introductionmentioning

confidence: 73%

Saturated absorption and crossover resonances in a high-finesse cavity: Formalism and application to the hyperfine structure of jet-cooled NO2by saturated-absorption cavity-ring-down spectroscopy

Dupré

2012

Phys. Rev. A

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“…The match between observed and calculated spectra in Fig. 1 will be seen to be exact in every detail, including weak crossover resonances and all intensities [17]. The fit is well conditioned, and converges strongly even if all parameters are originally set to zero.…”

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confidence: 82%

Hyperfine lifting of parity degeneracy and the question of inversion in a rigid molecule

1993

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This Letter demonstrates that the parity degeneracy of isolated vibration-rotation states of a rigid molecule can be removed by hyperfine interactions. Hyperfine structures of infrared transitions in PH3 are obtained by saturation spectroscopy around 10 fim. One of these is used to demonstrate unequivocally that degenerate states of opposite parity are separated by the proton hyperfine interactions. We show that alternative explanations involving the physical inversion of the molecule are completely inconsistent with the details of the spectra obtained. In addition to the splitting conclusion, which has very wide generality, new confidence limits are placed on the possible inversion splitting.PACS numbers: 33.20.Ea, 35.20.Jv, 35.20.Sd The degrees of freedom of most molecules in their ground electronic levels can be divided among translations, vibrations, rotations, large amplitude motions, and nuclear spin. Among large amplitude motions inversion plays a peculiar role since parity, the associated quantum number, is always good because of the invariance property of space under inversion in the absence of weak interactions. When a molecule inverts freely it is not surprising to find that the degeneracy of levels of opposite parity is lifted. The first important result of this paper is to show experimentally, via the example of phosphine, that the degeneracy will be lifted even for a rigid molecule in which there is no inversion. We show, further, that this result is intimately connected to the Pauli principle and that there can be no essential degeneracy with parity.Following earlier work on hyperfine effects in ammonia, we will classify the vibration-rotation and hyperfine states of a rigid molecule such as phosphine (PH3) under the geometrical point group C-$ v [1,2] and use the Landau [3] and Berger [4] notations. The rovibrational states are characterized by quantum numbers / and k for total orbital angular momentum and its component along the symmetry axis, respectively, while A^l&l. v is the quantum number for vibrational excitation, and / is the quantum number for the corresponding component of angular momentum along the symmetry axis. Thus, for example, the degenerate V4 state excited to the level 1*4-1 has / = ± 1. Finally, the parity, r =( ± ), completes the description of the rovibrational states. For symmetric top molecules, it is convenient to introduce the symmetric (s) and antisymmetric (a) character of a state upon reflection in a plane perpendicular to the symmetry axis. The correspondence between r and v is r =(+) if v ~(s) and K even or if v=(a) and K odd; otherwise, r^C -). States having k~l -± 3n form a representation A\+Ai except when k ~/=0, the states then being either A\ or A2 depending upon J and r. States having k -I = ± (3n + 1) or ± On 4-2) are of symmetry E. /p, the nuclear spin of 3l P, is j and the corresponding symmetry must necessarily be A\ as the atom is certainly on the symmetry axis. Then, the total proton spin, l\\, must be included. Proton spin states with I\\ = j and /H -...

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“…The AC* 0 lines are usually too weak and too close to AC = 0 lines to be observed directly but fortunately in saturation spectroscopy, crossover resonances appear halfway between two resonances that share a common state (if their frequency separation is within the Doppler width) and the crossover intensities are roughly the geometrical means between those of the parent lines. 5 Figure 1 illustrates the case of an F x -F 2 doublet. The VR splitting in the v 3 = 1 state (primarily due to the constant t 224 »t 044 ) is usually orders of magnitude larger than in the ground vibrational state.…”

mentioning

confidence: 99%

Breakdown of the Point-Group Symmetry of Vibration-Rotation States and Optical Observation of Ground-State Octahedral Splittings ofS32

Bordé

Salomon

et al. 1980

Phys. Rev. Lett.

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Intensities of hyperfine components in saturation spectroscopy

Cited by 54 publications

References 10 publications

Saturated absorption and crossover resonances in a high-finesse cavity: Formalism and application to the hyperfine structure of jet-cooled NO2by saturated-absorption cavity-ring-down spectroscopy

Saturated absorption and crossover resonances in a high-finesse cavity: Formalism and application to the hyperfine structure of jet-cooled NO2by saturated-absorption cavity-ring-down spectroscopy

Hyperfine lifting of parity degeneracy and the question of inversion in a rigid molecule

Breakdown of the Point-Group Symmetry of Vibration-Rotation States and Optical Observation of Ground-State Octahedral Splittings ofS32

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