Spatial resolution of optoacoustic laser-radiation detectors

A high-molutioo photoacoustic Ramao spectroscopy experiment is described. The resolution achieved by using two single-mode pulsed lasers is about 0.0054 em-' (full width at half maximum intensity). The experiment was tested first 00 the v,yZv, bands of CO, and gave an increase of at least about one order of magnitude in the signal-tonoise ratio with respect to stimulated Raman spectroscopy at low pressure (ca. 10 Torr x 1.3 kPa). The sensitivity is also demonstrated by the study of the weak hot band v1 + v, -v2 of CO, . In both cases, the experimental line shape is well reproduced by taking into account Doppler and collisional effects. A comparison with CARS spectra was also made.

show abstract

High‐resolution photoacoustic Raman spectroscopy of gases

Rotger

Lavorel

Chaux

1992

J Raman Spectroscopy

View full text Add to dashboard Cite

show abstract

Vibrational and rotational collisional relaxation in CO2–Ar and CO2–He mixtures studied by stimulated Raman-infrared double resonance

Deroussiaux

Lavorel

1999

The Journal of Chemical Physics

View full text Add to dashboard Cite

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 v1 or 2v2(Σ+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 v1 and population of 2v2 levels through a five-level model. A full set of vibrational rates has been determined and compared with other experimental and theoretical works when available. Our measurements could stimulate new accurate calculations. The rotational energy transfer among the J-resolved rotational levels of 2v2 has been observed for J=14 to 34 with a maximum difference between pumped and probed levels of ΔJ=20. The numerous experimental data have been modeled through a relaxation model based on the energy corrected sudden (ECS) approximation. The adjustable parameters of the ECS matrix have been directly determined by fitting the experimental time-dependent population curves. The diagonal elements of this matrix agree well with experimental linewidths. The resulting ECS relaxation matrix can be used to calculate line shapes in high-pressure coherent Raman spectra of v1 and 2v2 bands or infrared absorption spectra. In contrast, the inelastic linewidths of 2v2 deduced from depopulation data are in disagreement with available experimental linewidths, as already shown in numerous previous studies of gases and mixtures.

show abstract

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

customersupport@researchsolutions.com

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Spatial resolution of optoacoustic laser-radiation detectors

Cited by 2 publications

References 1 publication

High‐resolution photoacoustic Raman spectroscopy of gases

High‐resolution photoacoustic Raman spectroscopy of gases

Vibrational and rotational collisional relaxation in CO2–Ar and CO2–He mixtures studied by stimulated Raman-infrared double resonance

Contact Info

Product

Resources

About