Henri Damany

Pulsed-laser-generated rare-gas plasma as a light source in the vacuum ultraviolet

The plasma generated by focusing a 20-Hz, 330-mJ, Nd:YAG laser pulse in a rare gas at pressures from 1 to 6 bars is proposed as a source of a VUV continuum giving as many as 10(9) photons nm(-1) sec(-1) near 170 nm. Its stability makes it suited to VUV spectrophotometry. The pulse duration, ranging from 20 nsec for Ne to 40 nsec for Kr, should also permit its use in time-resolved spectroscopy.

Pressure effect on 6p-6s ir decay in xenon after two-photon excitation

Abstract Pressure effects on the decay rates of the Xe 6p[ 1 2 ]0 (0–800 mbar) and 6p[ 3 2 ]2 (0–200 mbar) levels have been measured up to 6 × 108 s−1 using two-photon excitation. An analysis in terms of binary and ternary total quench rates for both transitions is presented. A radiative lifetime of 28.2 ± 0.5 ns has been found for both 6p[ 1 2 ]0→6s[ 3 2 ]01 (828.0 nm) and 6p[ 3 2 ]2→6s[ 3 2 ]02 (823.2) transitions.

Pressure induced configuration demixing in the electronic spectrum of NO

Abstract Previous low resolution studies indicated that, in the absorption spectrum, transitions to Rydberg states are far more sensitive to pressure than transitions to valence states in accordance with the complete vanishing of Rydberg bands and the deperturbation of the valence bands in the spectrum of NO trapped in a solid rare gas matrix. The present study of NO is the first extensive investigation of medium and high resolution molecular electronic spectra subjected to pressure of foreign gases. It is observed that, at the highest pressure attained (∼1000 bar), almost all of the Rydberg bands have vanished whereas the remaining valence bands stay relatively sharp. While high pressure medium resolution spectra give information about the deperturbation of intensities and of vibrational spacings of the valence bands, inspection of low pressure high resolution spectra reveals that the rotational lines react to pressure in a way reflecting closely the degree of configuration mixing between Rydberg and valence states.

Pressure effects on the vibronic transitions of NH3 and NO

Abstract Medium resolution spectra of molecules subjected to a pressure of argon indicate a broadening and a shift of Rydberg transitions, dependent on the shape of the outer orbital. Valence transitions are comparatively little affected even at 200 bar. In the case of the very complicated spectrum of NO, the washing out of the Rydberg bands allows the valence bands to show up even at a moderate pressure, so that the spectrum tends toward the spectrum of NO isolated in a solid rare gas matrix, from which spectrum discrete Rydberg bands are absent. Vibronic terms in homogeneous interaction behave, under pressure, in a way which reflects closely their degree of interaction in the free molecule.

Improved cell design for pulsed dye lasers

A clean demountable dye cell is described which is more advantageous than the usual commercial cuvettes for obtaining good quality light beams from pulsed dye lasers.

Proprietes optiques de la calcite dans la region de Schumann

Abstract The four optical constants of calcite are determined from reflectance measurements with polarized light. In the curve of k o a wide band observed between 1400 and 1700 A is associated with a planar excited state of the CO 2- 3 .

Optical-optical double resonance involving the coupling of a vacuum-ultraviolet spark source with a laser: two-step excitation in rare gases

An experimental setup including the synchronized coupling of a VUV spark source with a laser is described. Experimental results on the depletion of Ar(2), Kr(2), and Xe(2) excimer fluorescence illustrate the capability of the system.

Proprietes optiques de la dolomite dans la region de schumann

Abstract The four optical constants of dolomite are determined from reflectance measurements with polarized light. A wide band observed between 1400 and 1800 A is associated, as for calcite, with a transition to a non-planar excited state of the CO 2- 3 .

Determination des indices d'absorption de la calcite dans la region d'absorption dichroïque (1910-1690Å)

Resume Absorption indices of calcite in the 1910-1690 A region have been determined from transmittance at non normal incidence of polished thin calcite plates cut obliquely to the optic axis.

Proprietes optiques de la magnesite dans la region de Schumann

Abstract The four optical constants of magnetise have been determined from reflectance measurements with polarized light. As in the case of calcite and dolomite, a wide band between 1300 and 1700 A is observed in the curve of ko and it arises from a transition of the planar CO2-3 to a non-planar excited state.