Journal ArticleDOI
Doppler‐limited spectroscopy at cryogenic temperatures: Application of collisional cooling
D. Newnham,J. Ballard,M. Page +2 more
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In this paper, a gas cell for the measurement of mid-infrared spectra of gases at cryogenic temperatures as low as 77 K is described, which allows it to be operated in collisional cooling (or diffusive trapping) mode to generate significant nonequilibrium pressures of monomer vapor for gases which would normally have vanishingly small vapor pressure at low temperatures.Abstract:
A coolable gas cell for the measurement of mid‐infrared spectra of gases at cryogenic temperatures as low as 77 K is described. The design of the cell allows it to be operated in collisional cooling (or diffusive trapping) mode to generate significant nonequilibrium pressures of monomer vapor for gases which would normally have vanishingly small vapor pressure at low temperatures. Fourier transform infrared spectra of carbon dioxide (CO2), nitrogen dioxide (NO2), and methyl silane (CH3SiH3) vapors cooled by collisions with helium gas at 77 K are reported. Sufficiently high concentrations of monomer gas may be produced at low total pressure conditions (<10 h Pa) to allow spectra to be recorded at the Doppler resolution limit. The resulting spectroscopic simplification indicates that efficient collisional cooling of the vibrational, as well as rotational, degrees of freedom occurs.read more
Citations
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Journal ArticleDOI
Liquid-helium temperature long-path infrared spectroscopy of molecular clusters and supercooled molecules
TL;DR: In this paper, a new method of collisional cooling is presented, based on a cooling cell with integrated temperature-invariant white optics and pulsed or continuous sample-gas inlet.
Journal ArticleDOI
The submillimeter: A spectroscopist’s view
TL;DR: The submillimeter spectral region has undergone an explosive growth in the last decade, not only in its impact on the larger scientific and technological world, but also in the high resolution laboratory spectroscopy that makes much of this success possible.
Journal ArticleDOI
Large molecular aggregates: From atmospheric aerosols to drug nanoparticles.
TL;DR: The present contribution is focused on the characterization of the physical-chemical properties of large molecular aggregates and on their targeted generation, focusing on the vibrational dynamics of these particles.
Journal ArticleDOI
A slow, continuous beam of cold benzonitrile.
David Patterson,John M. Doyle +1 more
TL;DR: A cold, continuous, high flux beam of benzonitrile has been created via buffer gas cooling, demonstrating a new source for high resolution spectroscopy and providing an attractive starting point for further spatial manipulation of such molecules, including eventual trapping.
Journal ArticleDOI
Theoretical and experimental investigation of pressure broadening and line shift of carbon monoxide in collision with hydrogen between 8 and 600 K
TL;DR: In this paper, pressure broadening and line shift parameters for the J=1←0 and J=2←1 transitions of carbon monoxide (CO) in collision with hydrogen (H2) at various temperatures between 8 and 600 K were measured.
References
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Journal ArticleDOI
Rate constants for the reactions of CN with hydrocarbons at low and ultra-low temperatures
Ian R. Sims,Jean-Louis Queffelec,D. Travers,Bertrand R. Rowe,Lee B. Herbert,Joachim Karthäuser,Ian W. M. Smith +6 more
TL;DR: In this paper, the pulsed laser-photolysis (PLP), time-resolved laser-induced fluorescence (LIF) technique has been used to study the reactions of the CN radical with CH 4, C 2 H 6, C 2H 4 and C 3 H 6 at low and ultra-low temperatures.
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Journal ArticleDOI
Measurement of Pressure-Broadening Parameters for the CO-He System at 4 K
J. K. Messer,Frank C. De Lucia +1 more
TL;DR: In this paper, the rotational energy-level separation of CO collisions with helium at 4 K was measured and found to be 10.1 and 11.2 MHz/Torr (half width at half maximum).