Accession Number:

ADA002228

Title:

Double Absorption Photofragment Spectroscopy, A New Tool for Probing Unimolecular Process,

Descriptive Note:

Corporate Author:

CALIFORNIA UNIV SAN DIEGO LA JOLLA DEPT OF CHEMISTRY

Personal Author(s):

• Sander,R. K.
• Wilson,K. R.

Report Date:

1974-10-01

Pagination or Media Count:

54.0

Abstract:

A new technique, Double Absorption Photofragment Spectroscopy DAPS, has been developed for observing the time evolution of unimolecular processes. Molecules isolated from collisions in a molecular beam are prepared in a well defined intermediate state by an initiation laser pulse. As this state evolves in time, it is monitored by a second probe laser pulse which, after a chosen delay, photodissociates the molecules. Information about the state to which the molecules have evolved by the time of the probe pulse can be extracted from the mass, density, angular and energy distributions of the recoiling fragments. Simple models are explored for the functional form of the angular distributions which can be expected in DAPS experiments. Future DAPS experiments should be able to observe unimolecular electronic and nuclear change over a time span from 10 to the -12th power to 10 to the -3rd power seconds, probing such processes as rearrangement, dissociation, internal vibrational transfer, intersystem crossing and internal conversion.

Descriptors:

• *MOLECULAR SPECTROSCOPY
• *PHOTODISSOCIATION
• DISTRIBUTION
• LASER BEAMS
• MOLECULAR BEAMS
• LIGHT PULSES
• PARTICLE COLLISIONS
• MOLECULAR ENERGY LEVELS
• MASS SPECTRA

Subject Categories:

• Radiation and Nuclear Chemistry
• Atomic and Molecular Physics and Spectroscopy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE