Search results for "DOUBLE-RESONANCE"
showing 8 items of 8 documents
Stimulated Raman and Cars Spectroscopy of ν1 and 2ν2 (A1) Bands of 12CF4
1994
Two experimental coherent Raman techniques, stimulated Raman and coherent anti-Stokes Raman spectroscopy (CARS), were employed to study the Raman spectrum of CF 4 in the 900 cm −1 region. The stimulated Raman and CARS spectra of the ν 1 band of CF 4 were recorded at high resolution. The analysis of these spectra enabled some spectroscopic constants of this band to be refined and higher order constants to be determined for the first time. The first high-resolution CARS spectrum of the 2ν 2 (A 1 ) harmonic band is also presented. The rotational transitions of this band up to J = 40 were assigned and the first set of spectroscopic constants for this sub-level were determined. These results imp…
Analysis of Infrared and Raman-Spectra of 116SnH4 in the 1900 cm-1 Region - Study of the 1000, 0010 Interacting States
1991
0022-2852
Collisional Broadening, Line Shifting, and Line Mixing in the Stimulated Raman 2-v2 Q-Branch of CH4
1991
0021-9606; Self-, argon-, and helium-broadening coefficients have been measured for 13 lines in the 2v2 Raman Q branch of CH4 using stimulated inverse Raman spectroscopy. The linewidths clearly show the symmetry-state dependence characteristic of pressure broadening, and inelastic processes in general, involving spherical-top molecules. Pressure-induced line shifts have also been measured for these features in pure methane. The pressure-shift coefficients do not display the symmetry-state dependence found for the linewidths. By applying the Rosenkranz perturbation treatment to a pair of collisionally mixed lines, we have been able to obtain an estimate of individual state-to-state contribut…
Collisional Broadening of Rotational Lines in the Stimulated Raman Pentad Q-Branch of CD4
1992
Self- and argon-broadening coefficients are reported for a number of Raman Q-branch transitions in the nu(1) and nu(2) + nu(4) bands of (C-12)D4 at room temperature (296 K). The coefficients display a variation with j and with C exp n (symmetry species A, E, F) that is essentially independent of collision partner and which is similar to the j- and C exp n-dependence found in previous measurements of the IR line-broadening coefficients. The rotationally inelastic collision rates previously measured by Foy et al. (1988) for (C-13)D4 (V4 = 0, 1) in collision with (C-13)D4 or Ar account for only a part of the Raman broadening rate, suggesting possibly significant contributions to the linewidths…
Line mixing in the ν1 and 2ν2 isotropic Raman Q-branch of CO2 perturbed by argon and helium
1999
0021-9606; The shapes of the ν1 and 2ν2 isotropic Raman Q-branch of CO2 perturbed by argon and helium have been measured by Stimulated Raman Spectroscopy (SRS) or coherent anti-Stokes Raman Spectroscopy (CARS) techniques. The data have been successfully analyzed with an energy corrected sudden (ECS) approximation model based on basic rates determined independently. Finally comparison of the present data with time resolved double resonance experiments allows us to discuss the physical origin of the two empirical constants which account for the shift and broadening of the branch due to vibrational effects. (C) 1999 American Institute of Physics. [S0021-9606(99)00344-X].
Vibrational and rotational collisional relaxation in CO2–Ar and CO2–He mixtures studied by stimulated Raman-infrared double resonance
1999
0021-9606; The collisional relaxation among vibrational levels of the Fermi dyad of CO2 mixed with Ar and He (10% CO2, 90% rare gas) has been studied at room temperature with a double resonance experiment. Stimulated Raman effect from the ground state achieved the pumping process with a Nd:YAG laser and a pulse amplified dye laser. After pumping the v(1) or 2v(2)(Sigma(+)g) level, a cw CO2 laser was used to probe either the depopulation rates of the pumped levels (vibrationally or rotationally resolved) or the energy transfer rates to neighboring states. The vibrational energy relaxation has been studied from experimental depopulation of v(1) and population of 2v(2) levels through a five-le…
Magnetic octupole moment of Yb-173 using collinear laser spectroscopy
2021
The hyperfine constants of the $4{f}^{14}6s6p^{3}P_{2}^{o}$ state in neutral Yb have been measured using three different dipole transitions. This state was recently shown to have a comparatively large hyperfine magnetic octupole splitting, and thus a puzzlingly large magnetic octupole moment. The measurement is performed using collinear laser spectroscopy on a fast atomic beam, which provides a straightforward route to probing long-lived metastable atomic states with high resolution. From the combined analysis of all three lines we find no significant evidence for a nonzero octupole moment in $^{173}\mathrm{Yb}$.
Measurements of Collisional Line Widths in the Stimulated Raman Q-Branch of the v1 Band of Silane
1990
0377-0486; Self-broadened widths of 28SiH4 in the v1 Q-branch have been measured at room temperature (295 K) using high-resolution stimulated Raman spectroscopy. These collisional widths have been obtained by fitting a superposition of Voigt profiles to the experimental spectra in the pressure range 28-154 Torr. No evidence for line mixing within the tetrahedral components of a Q(J) line has been found. The line broadening coefficients for J up to 13 depend weakly on the rotational quantum number. The mean value is 103.7 x 10(-3) cm-1 atm-1.