Coherent anti-Stokes Raman spectroscopy of shock-compressed liquid oxygen

Journal Article · Thu Nov 30 23:00:00 EST 1989 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.457345· OSTI ID:5168053

Schmidt, S C; Moore, D S; Shaw, M S; Johnson, J D ^[1]

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1. Los Alamos, New Mexico 87545 (US)

Vibrational spectra of liquid oxygen, shock compressed to several high-pressure/high-temperature states, were obtained using single-pulse multiplex coherent anti-stokes Raman scattering (CARS). The experimental spectra were compared to synthetic spectra calculated using a semiclassical model for the CARS intensities and best fit vibrational frequencies, peak Raman susceptibilities, and Raman linewidths. Up to the maximum shock pressure of 9.6 GPa, the vibrational frequencies were found to increase monotonically with pressure. An empirical fit, which could be used as a pressure/temperature/frequency calibration standard, showed that the Raman frequency shifts could be accurately described by linear pressure and temperature dependences. Above {approx}9 GPa, the liquid oxygen opacity at 632.8 nm increased rapidly, presumably because of proximity (collision)-induced absorption. Calculations showed that the induced absorption did not resonantly enhance the CARS spectra, but did attenuate the laser beams and the CARS signals. The measured linewidths suggest that the vibrational dephasing time decreased to approximately 1 ps at the highest pressures.

• OSTI ID: 5168053
• Journal Information: Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 91:11; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE
450100* -- Military Technology
Weaponry
& National Defense-- Chemical Explosions & Explosives
CHEMICAL EXPLOSIVES
COMPRESSION
DENSITY
ELEMENTS
ENERGY LEVELS
EXCITED STATES
EXPLOSIVES
FLUIDS
LASER SPECTROSCOPY
LINE WIDTHS
LIQUIDS
NONMETALS
OXYGEN
PHYSICAL PROPERTIES
PRESSURE DEPENDENCE
RAMAN SPECTRA
RAMAN SPECTROSCOPY
SHOCK WAVES
SPECTRA
SPECTROSCOPY
TEMPERATURE DEPENDENCE
VERY HIGH PRESSURE
VERY HIGH TEMPERATURE
VIBRATIONAL STATES