Computer-controlled Raman spectrometer for time-resolved measurements in low pressure gaseous sample

Abstract:

A spectrometer for measuring spontaneous Raman scattering in gaseous samples at pressures below 100 Pa (0.75 torr) with nanosecond time resolution is presented. The apparatus was developed for studying intramolecular vibrational energy distributions in infrared multiphoton excited molecules, and makes it possible to study the anti-Stokes Raman scattering from isolated molecules at pressures down to 14 Pa (110 mtorr). Because of the low level of the signals the measurements are completely computer-controlled. A detailed description of the apparatus, including the multichannel data-acquisition hardware and computer interface, is