Numerical pattern recognition analysis of acetylene dispersed fluorescence spectra

Journal Article · Fri May 01 04:00:00 EDT 1998 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.476127· OSTI ID:627741

OBrien, J P; Jacobson, M P; Sokol, J J; Coy, S L; Field, R W ^[1]

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1. Department of Chemistry and George R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts02139 (United States)

Polyad quantum numbers have been assigned to 134 vibrational levels of the {tilde X}{sup 1}{Sigma}{sub g}{sup +} state of acetylene with internal energies from 3,000 to 15,000 cm{sup {minus}1}. These polyad assignments have been made possible by two advances: (1) the recording of new, rigorously calibrated acetylene {tilde A}{sup 1}A{sub u}{r_arrow}{tilde X}{sup 1}{Sigma}{sub g}{sup +} dispersed fluorescence spectra, and (2) the development of a numerical pattern recognition technique which identifies groups of transitions in the spectra that terminate on eigenstates with the same polyad quantum numbers. This pattern recognition technique is based on the Extended Cross-Correlation, which has been reported previously in this Journal [J. Chem. Phys. {bold 107}, 8349, 8357 (1997)], and requires neither {ital a priori} knowledge of the number of polyads in the spectra nor the pattern of spectral lines that is associated with each polyad. No evidence for the breakdown of the polyad quantum numbers is found, at the 7 cm{sup {minus}1} resolution of our spectra, at internal energies up to at least 15,000 cm{sup {minus}1}. The ability to assign polyad quantum numbers to spectral features with up to 15,000 cm{sup {minus}1} of internal energy provides a panoramic perspective on the trends in the short-time ({approximately}1 ps) dynamics of acetylene at high internal energy. {copyright} {ital 1998 American Institute of Physics.}

• OSTI ID: 627741
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 17 Vol. 108; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ACETYLENE
ELECTRONIC STRUCTURE
FLUORESCENCE
PATTERN RECOGNITION
QUANTUM NUMBERS
VIBRATIONAL STATES