High-resolution spectroscopy of (pentad-dyad) and (octad-pentad) hot bands of methane in a supersonic jet

Journal Article · Fri Oct 01 00:00:00 EDT 1993 · Journal of Molecular Spectroscopy; (United States)

DOI:https://doi.org/10.1006/jmsp.1993.1249· OSTI ID:5623869

Hilico, J C ^[1]; Baronov, G S; Bronnikov, D K; Gavrikov, S A; Nikolaev, I I; Rusanov, V D; Filimonov, Yu G ^[2]

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1. Univ. de Bourgogne, Kijon (France)
2. Russian Scientific Centre, Moscow (Russian Federation)

Pulsed jets of heated methane (850 K) have been investigated by high-resolution diode laser spectroscopy in the 8-[mu]m region. The observation of hot band transitions with lower states as high as 3000[sup [minus]1] shows that the cooling effect does not modify the distribution of levels between the vibrational polyads. Among the 45 observed lines in the narrow ranges which have been recorded, 18 have been assigned to (pentad-dyad) and 21 to (octad-pentad) transitions. If a common rotational temperature is assumed, a full description of the energy distribution in the hot jet requires the definition of a vibrational temperature for each polyad. A rotational temperature of 200 [+-] 10 K has been deduced from the analysis of the strengths of the 2v[sub 3] Q-branch lines at 1.66 [mu]m. Vibrational temperatures for distributions between polyads and for dyad and pentad cases have been found to be 830 [+-] 70, 220 [+-] 25, and 360 [+-] 80 K, respectively.

• OSTI ID: 5623869
• Journal Information: Journal of Molecular Spectroscopy; (United States), Vol. 161:2; ISSN 0022-2852
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
METHANE
LASER SPECTROSCOPY
ENERGY SPECTRA
ENERGY-LEVEL TRANSITIONS
SUPERSONIC FLOW
TEMPERATURE RANGE 0400-1000 K
VIBRATIONAL STATES
ALKANES
ENERGY LEVELS
EXCITED STATES
FLUID FLOW
HYDROCARBONS
ORGANIC COMPOUNDS
SPECTRA
SPECTROSCOPY
TEMPERATURE RANGE
400102* - Chemical & Spectral Procedures