Experimental Determination of the 1 Sigma(+) State Electric-Dipole-Moment Function of Carbon Monoxide up to a Large Internuclear Separation

Experimental intensity information is combined with numerically obtained vibrational wave functions in a nonlinear least squares fitting procedure to obtain the ground electronic state electric-dipole-moment function of carbon monoxide valid in the range of nuclear oscillation (0.87 to 1.01 A) of about the V = 38th vibrational level. Mechanical anharmonicity intensity factors, H, are computed from this function for delta V + = 1, 2, 3, with or = to 38

Adaptive dual-comb spectroscopy in the green region

Dual-comb spectroscopy is extended to the visible spectral range with a set-up based on two frequency-doubled femtosecond ytterbium-doped fiber lasers. The dense rovibronic spectrum of iodine around 19240 cm-1 is recorded within 12 ms at Doppler-limited resolution with a simple scheme that only uses free-running femtosecond lasers

Raman-induced Kerr-effect dual-comb spectroscopy

We report on the first demonstration of nonlinear dual-frequency-comb spectroscopy. In multi-heterodyne femtosecond Raman-induced Kerr-effect spectroscopy, the Raman gain resulting from the coherent excitation of molecular vibrations by a spectrally-narrow pump is imprinted onto the femtosecond laser frequency comb probe spectrum. The birefringence signal induced by the nonlinear interaction of these beams and the sample is heterodyned against a frequency comb local oscillator with a repetition frequency slightly different from that of the comb probe. Such time-domain interference provides multiplex access to the phase and amplitude Raman spectra over a broad spectral bandwidth within a short measurement time. Experimental demonstration, at a spectral resolution of 200 GHz, a measurement time of 293 {\mu}s and a sensitivity of 10^-6, is given on liquid samples exhibiting a C-H stretch Raman shift.Comment: 7 pages, 4 figure

NEW YEAR INFRARED WAVENUMBER STANDARDS BY FOURIER SPECTROSCOPY IN VACUUM

$^{1}$ D.H. Rank, A.H. Guenther, G.D. Saksena, J.N. Shearer and T.A. Wiggins, J. Opt. Soc. Am. 47, 8, 686 (1957). $^{2}$ G. Guelachvili, Nouv. Rev. Optique Appliquee 3, 6, 317 (1972). $^{3}$ G. Guelachvili, These ORSAY (1973). $^{4}$ P. Heminger, F.C. De Lucia and W. Gordy, Phys. Rev. Lett. 25, 20, 1397 (1970).Author Institution: Laboratoire AIME COTTONThe 2 -- 0 band lines of $^{12}C^{16}O$, at about $4260 cm^{-1}$, are the most frequently used ones for the wavenumber calibration of near infrared spectrometers. The values of these wavenumbers, up to now considered as standards, have been given a long time ago by D.H. Rank and his co-workers$.^{1}$ The High Information Fourier Spectrometer, built at Laboratoire AIME COTTON, is now operating in $Vacuum^{2}$ and provides absolute wavenumber measurements. It has been used to measure the 2 - 0 band of $^{12}C^{16}O,$ which lines were directly referred, in the experiment, to the Krypton 86 Standard line at 16 $507.6373 cm^{-1}$. The estimated relative error on the lines position is $3 \times 10^{-8}$. The relative precision is increased by 16 when compared with that of the previous standards. Comparison between the two sets of CO lines shows some discrepancies. The $B_{0}$ rotational $constant^{3}$ leads, combined with the $B_{0}$ value given by P. Heminger $et al^{4}$ leads to the following Velocity of Light $c = 299 792.46 ( \pm 0.070)$ km/s. The precision on the i.r. and the r.f. $B_{0}$ rotational constant values have the same order of magnitude

N2O,H2ON_{2}O, H_{2}O WAVELENGTH STANDARDS IN THE 5−10μ5 - 10 \mu RANGE, DUNHAM COEFFICIENTS OF CO

New wavenumber standards are measured by F.T.S. in vacuum. $N_{2}O$ lines extend from about 1100 to $1350 cm^{-1}$. Their accuracy is of the order of 50 to 150 $10^{6} cm^{-1}$. The water lines are obtained with a similar accuracy on a wider range. These data measured for the first time with a high information technique are located in a spectral area where experimental wavenumber references were up to now practically absent. They should be useful for accurate calibration of diode and Fourier spectra. An extensive work on CO covering a large domain of vibration and rotation quantum numbers in the fundamental electronic state $X^{1}\Sigma$, is reported

NEW DETERMINATION OF INFRARED WAVELENGTH STANDARDS BY VACUUM FOURIER SPECTROSCOPY

Author Institution: Laboratoire Aim\'{e} Cotton, C. N. R. S. IINew wavelength standards are obtained in the $2000 cm^{-1}$ spectral region. They consist of lines belonging to the vibration-rotation spectra of $H_{2}O$, $CO_{2}$, CO molecules and some of their isotopic species. Their measurement has been performed with reference to the krypton - 84 Length Etalon by using 2-0 CO band lines previously determined on the same apparatus with an estimated relative error of 3 $\times$ 10$^{-8}$