C. Leroy

Analysis of highly excited ‘hot’ bands in the SO2 molecule: ν2 + 3ν3 − ν2 and 2ν1 + ν2 + ν3 − ν2

We set up a variational procedure of assignments of transitions and we applied it to the analysis very weak ‘hot’ bands, ν2 + 3ν3 − ν2 and 2ν1 + ν2 + ν3 − ν2, of the SO2 molecule. As the first step of the study, the ‘cold’ bands, 3ν3 and 2ν1 + ν3, are re-analysed and transitions belonging to those bands are assigned up to the values of quantum numbers J max. = 60, , and J max. = 69, for the bands 3ν3 and 2ν1 + ν3, respectively. After ‘cleaning’ the experimental spectrum from transitions belonging to the 3ν3 and 2ν1 + ν3 bands, a variational procedure was used that allowed us to assign 230 and 115 transitions with the values of quantum numbers J max. = 35, , and J max. = 26, for the bands ν2 + 3ν3 − ν2 and 2ν1 + ν2 + ν3 − ν2, respectively. The sets of spectroscopic parameters obtained by fitting the assigned experimental transitions reproduce the initial experimental data with an accuracy close to experimental uncertainties.

Hyperfine Paschen–Back regime realized in Rb nanocell

A simple and efficient scheme based on a one-dimensional nanometric-thin cell filled with Rb and strong permanent ring magnets allows direct observation of the hyperfine Paschen-Back regime on the D(1) line in the 0.5-0.7 T magnetic field. Experimental results are perfectly consistent with the theory. In particular, with σ(+) laser excitation, the slopes of the B-field dependence of frequency shifts for all 10 individual transitions of (85,87)Rb are the same and equal to 18.6 MHz/mT. Possible applications for magnetometry with submicron spatial resolution and tunable atomic frequency references are discussed.

The local group K(4) in the algebraic approach to vibrational spectra of tetrahedral molecules: Application to silane

Abstract In a previous paper, Michelot and Moret-Bailly ( J. Phys. , 48 , 51 (1987)) proposed an algebraic treatment of vibrational stretching modes in polyatomic molecules. They used the properties of the group chain U ( p + 1) ⊃ U ( p ) ⊃ S ( p ) ⊃ G for the study of p identical oscillators. The molecule, with p equivalent bonds described as a system of p oscillators, has a symmetry group G . We develop in this paper an application to p = 4 equivalent oscillators. We show that, for a tetrahedral molecule, the group chain U (5) ⊃ U (4) ⊃ S (4) ≈ T d can be completed, in a local point of view, with a particular group K (4): U(5) ⊃ U(4) ⊃ K(4) ⊃ S(4) ≈ T d This group provides us with available labels which clearly identify the different local states. A set of K (4) invariants allows the straightforward computation of the energy of these states. We apply our model to the silane molecule.

High contrast D 1 line electromagnetically induced transparency in nanometric-thin rubidium vapor cell

The electromagnetically induced transparency (EIT) on the atomic D1 line of rubidium is studied using a nanometric-thin cell with atomic vapor column length in the range of L=400–800xa0nm. It is shown that the reduction of the cell thickness by four orders as compared with an ordinary cm-size cell still allows to form an EIT resonance for L=λ=794xa0nm with the contrast of up to 40%. Further reduction of thickness to L=λ/2 leads to significant reduction of EIT contrast, verifying that the key parameter for EIT in wavelength-scale-thickness cells is not the value of L itself but L/λ ratio. Remarkable distinctions of EIT formation in nanometric-thin and ordinary cells are demonstrated. Well-resolved splitting of the EIT resonance in a magnetic field for L=λ can be used for magnetometry with nanometric spatial resolution. The presented theoretical model well describes the observed results.

Complete hyperfine Paschen-Back regime at relatively small magnetic fields realized in potassium nano-cell

A one-dimensional nano-metric-thin cell (NC) filled with potassium metal has been built and used to study optical atomic transitions in external magnetic fields. These studies benefit from the remarkable features of the NC allowing one to use

High-Spatial-Resolution Monitoring of Strong Magnetic Field using Rb vapor Nanometric-Thin Cell

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Hyperfine Paschen–Back regime in alkali metal atoms: consistency of two theoretical considerations and experiment

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On the ‘expanded local mode’ approach applied to the methane molecule: isotopic substitution CH2D2 ←CH4

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Theory of the bright-state stimulated Raman adiabatic passage

-methods for effective investigations of individual transitions of the K D_1 line. The methods are based on strong narrowing of the absorption spectrum of the atomic column of thickness L equal to

Decoupling of hyperfine structure of Cs D_1 line in strong magnetic field studied by selective reflection from a nanocell

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