Accession Number:

ADA399721

Title:

Long-Lived, Energetic States of Small Molecules: Spectroscopy, Pattern Recognition, and Formation/Destruction Mechanisms

Descriptive Note:

Final technical rept. 1 Jan 1997-31 Dec 2000

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE

Personal Author(s):

Report Date:

2002-02-01

Pagination or Media Count:

31.0

Abstract:

Metastable, electronically excited states of atoms and small molecules have chemical and photophysical properties that are relevant to Air Force missions in communication, upper atmospheric modeling, and high speed vehicle detection tracking, and identification A second-generation supersonic molecular beam apparatus with optimized multispectral capabilities has been designed, constructed, and tested. A series of experiments on acetylene has defined the fundamental mechanisms of three complementary signal channels UV-LIF Ultraviolet Laser Induced Fluorescence, IR-LIF Laser Induced infrared Fluorescence from photofragments and SEELEM Surface Electron Ejection from Laser Excited Metastable molecules. Simultaneous measurements of S1, T1 and T3 characters of each eigenstate permit the causal mechanisms of photoexcitation, intersystem crossing, and collisional deexcitation to be identified. Powerful statistical pattern-recognition techniques have been developed which permit the disentanglement of key structural and dynamical features in the spectra and the ability to distinguish between direct statistical and doorway-mediated causal limiting mechanisms for intersystein crossing.

Subject Categories:

  • Cybernetics
  • Atomic and Molecular Physics and Spectroscopy
  • Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE