NCJ Number
32107
Date Published
1975
Length
38 pages
Annotation
A REPORT ON A PRELIMINARY INVESTIGATION OF THE DOPPLER-FREE METHOD OF COUNTERPROPAGATING BEAM TWO-PHOTON SPECTROSCOPY FOR ITS APPLICATIONS TO EXPLOSIVE VAPOR DETECTION.
Abstract
THIS METHOD HOLDS GREAT PROMISE FOR PROVIDING DIRECT EXCITATION OF SINGLE ELECTRONIC STATES OF MOLECULES, THUS PERMITTING HIGHLY SELECTIVE MOLECULAR EXCITATION. INTERFERENCE EFFECTS FROM OTHER MOLECULAR SPECIES, WHICH EXHIBIT ABSORPTION BANDS IN THE SAME SPECTRAL REGION, WOULD THEREBY BE REDUCED. ABSORPTION-LINE NARROWING HAS BEEN OBSERVED FOR NITRIC OXIDE, AND RESOLVABLE SPECTRAL FEATURES HAVE BEEN RECORDED IN THE BENZENE ABSORPTION SPECTRUM. THE MOLECULAR STRUCTURE OF BENZENE RESEMBLES THAT OF EXPLOSIVE VAPORS. THE EXPERIMENTAL RESULTS OF THIS SIX-MONTH EFFORT CONFIRM THEORETICAL PREDICTIONS AND SUPPORT THE UNDERLYING HYPOTHESIS OF THIS INVESTIGATION. (AUTHOR ABSTRACT)