Knowledge Bank

For the past several years we have conducted $experiments1,2,3$ designed to investigate the storage, transfer and uses of vibrational energy in simple liquid systems. The liquids we have chosen for study are nitrogen or oxygen either neat or doped with small molecules such as $H2,D2,NO,CO,CO2,N2O,CH4,CH4$, or $CF4$. In our experiments a Q-switched ruby laser is fired into the liquid producing vibrational excitation by Stimulated Ramon Scattering. The transfer or decay of vibrational excitation is monitored by either spontaneous Raman scattering or infrared luminescence. The lifetime of vibrational excitation of a molecule in these systems varies enormously. For $N2\mathrm{<mrow\; data-mjx-texclass="ORD">\ast </mrow>}$ in liquid nitrogen this time is of the order of seconds while for $CD4\mathrm{<mrow\; data-mjx-texclass="ORD">\ast </mrow>}$ in liquid nitrogen the time is of the order of $10-9$ sec. The mechanisms for energy transfer in several of these systems will be discussed end models for understanding the vibrational lifetimes will be discussed.