Abstract

We are employing picosecond fluorescence spectroscopy and laser driven compressional shocks to study the energy transfer from macroscopic mechanical disturbance to intramolecular modes in condensed media. By compressional shock we mean a large amplitude material disturbance propagating at supersonic speed, across which the pressure, density, temperature and internal state of molecules change in a nearly stepwise fashion. A molecule in the path of such a disturbance witnesses a change from ambient to high pressure in a time on the order of a picosecond as the front passes. In general, the shock arises from an amplitude dependent wave velocity which causes the leading edge of a high pressure compressional wave to steepen as it propagates, eventually sharpening to a near discontinuity.

© 1984 Optical Society of America