Search results for "Quantum"

Investigation of the vibrational dynamics of the HCN/CNH isomers through high order canonical perturbation theory

2000

International audience; Molecular vibrations of the molecule HCN/CNH are examined using a combination of a minimum energy path Hamiltonian and high order canonical perturbation theory , as suggested in a recent work [D. Sugny and M. Joyeux, J. Chem. Phys. 112, 31 (2000)]. In addition, the quantum analog of the classical CPT is presented and results obtained therefrom are compared to the classical ones. The MEP Hamiltonian is shown to provide an accurate representation of the original potential energy surface and a convenient starting point for the CPT. The CPT results are subsequently used to elucidate the molecular dynamics: It appears that the isomerization dynamics of HCN/CNH is very tri…

Multispectrum fits for line mixing in the ν3 band Q branch of methane

2003

International audience; First-order line-mixing coefficients and model relaxation matrix element scaling factors have been obtained for allowed transitions in the nu3 band Q branch of CH4 broadened by H2, He, N2, O2, Ar, and CH4. The broadening, shifting, Dicke-narrowing, and line-mixing parameters are determined by simultaneous least-squares fitting of spectra at pressures from 0.014 to 66.66 kPa recorded with a high-resolution difference-frequency laser. These results confirm, improve, and extend a previous analysis of the lower pressure (613.3 kPa) data [A.S. Pine, J. Chem. Phys. 97 (1992) 773] which yielded averaged coefficients of individually fit spectra where adjacent broadened lines…

On the high resolution spectroscopy and intramolecular potential function of SO2

2009

Abstract Two weak stretching bands, ν 1  + 3 ν 3 and 3 ν 1  +  ν 3 , of the sulfur dioxide molecule have been recorded at high resolution and analyzed for the first time with using a Fourier transform Bruker IFS-120 HR interferometer. About 1000 transitions with J max .  = 51, K a max . = 16 , and 900 transitions with J max .  = 53, K a max . = 16 have been assigned to the bands ν 1  + 3 ν 3 and 3 ν 1  +  ν 3 , respectively. Analysis of the recorded spectra was made using the model of isolated vibrational states. Parameters obtained from the fit reproduce the initial experimental ro-vibrational energies with the rms deviation of 0.0006 and 0.0012 cm −1 for the bands, 3 ν 1  +  ν 3 and ν 1  …

Approche Unitaire en Spectroscopie Moléculaire

1996

International audience

Hyperfine Paschen-Back regime realized in Rb nanocell

2012

A simple and efficient scheme based on one-dimensional nanometric thin cell filled with Rb and strong permanent ring magnets allowed direct observation of hyperfine Paschen-Back regime on D1 line in 0.5 - 0.7 T magnetic field. Experimental results are perfectly consistent with the theory. In particular, with sigma+ laser excitation, the slopes of B-field dependence of frequency shift for all the 10 individual transitions of 85,87Rb 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.

Electromanetically Induced Resonances in Sub-Micron Thin Rb-Vapor Layer

2006

Dark-line Atomic Resonances in 1-100 µm-thin cells

2007

International audience; Recently developed micrometric thin cells (MTC) containing atomic vapor of micrometric column thickness allow one to study peculiarities of Electromagnetically Induced Transparency (EIT) phenomenon, along with the accompanying velocity selective optical pumping/saturation (VSOP) resonances. MTC are filled with pure Rb and neither buffer gas nor paraffin-coated walls were used. the Lambda-system on D2 lines of 85RB have been studied with the use of two separate diode lasers. There are several dramatic distinctions in formation of EIT and VSOP resonances in MTC as compared with conventional cm-size cells. Particularly, in the case of MTC the narrowest EIT resonance is …

Etude des Etats Vibrationnels Très Excités des Molécules Pyramidales Non Planes.

2006

High resolution study of the six lowest doubly excited vibrational states of PH2D

2005

Abstract The five lowest doubly excited deformational vibrational bands ν 4  +  ν 6 , 2 ν 6 , ν 3  +  ν 4 , ν 3  +  ν 6 , and 2 ν 3 of PH 2 D have been recorded for the first time using a Bruker 120 HR interferometer with a resolution 0.0033 cm −1 and analysed. Some transitions belonging to a very weak band 2 ν 4 have been also assigned. From the fit 24 and 86, respectively, diagonal and resonance interaction parameters were obtained which reproduce 1089 upper energy levels obtained from more than 4600 assigned transitions with the rms deviation of 0.00059 cm −1 .

The U(p+1) Formalism Applied to The Vibrational Hamiltonians of Nonlinear AB2 Molecules

2000