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

Journal Article · Tue Jan 31 23:00:00 EST 1989 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.456079· OSTI ID:6566225

Moore, D S; Schmidt, S C; Shaw, M S; Johnson, J D

Vibrational spectra of liquid nitrogen shock compressed to several high pressure/high temperature states were recorded using single-pulse multiplex coherent anti-Stokes Raman scattering. Vibrational frequencies, third-order susceptibility ratios, and linewidths are presented for the fundamental and several excited-state transitions. Vibrational frequencies were found to increase monotonically up to approx. =17.5 GPa single shock and approx. =30 GPa double shock. Above these pressures, the vibrational frequencies were observed to decrease with further increases in pressure. The decrease in vibrational frequency occurs in a pressure regime where the shocked nitrogen is becoming optically opaque. The consequence of the decrease in vibrational frequency on the Grueneisen mode gamma and its effect on the N/sub 2/ equation of state is discussed. The transition intensity and linewidth data suggest that thermal equilibrium of the vibrational levels is attained in less than 10 ns at these high pressures and temperatures. Finally, the measured linewidths exhibit an almost linear dependence on shock temperature, and also suggest that the vibrational dephasing time has decreased to less than 1 ps at the highest pressures.

• Research Organization: Los Alamos National Laboratory, Los Alamos, New Mexico 87545
• OSTI ID: 6566225
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 90:3; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
COHERENT SCATTERING
COMPRESSION
ELEMENTS
ENERGY LEVELS
EQUATIONS
EQUATIONS OF STATE
EXCITED STATES
FLUIDS
LASER SPECTROSCOPY
LIGHT SCATTERING
LINE WIDTHS
LIQUIDS
NITROGEN
NONMETALS
RAMAN SPECTROSCOPY
SCATTERING
SHOCK WAVES
SPECTROSCOPY
ULTRAHIGH TEMPERATURE
VERY HIGH PRESSURE
VIBRATIONAL STATES