https://doi.org/10.1007/s100530170250
Semi-classical analysis of helium broadened acetylene (ν1+3ν3) band transitions measured by a NIR diode laser spectrometer
Department of
Physics, University of Calcutta, 92 A.P.C. Road, Calcutta -
700 009, India
Corresponding author: a png@cubmb.ernet.in
Received:
27
July
2000
Revised:
15
November
2000
Published online: 15 March 2001
Helium-broadened line shapes of the rovibrational transitions of the
(
) combination-overtone band of C2H2have been studied by using a
near IR diode laser spectrometer. The 2f frequency detection
technique has been employed for signal detection of these weak band
transitions. The linestrength parameters and broadening coefficients
(HWHM) have been extracted by fitting the observed line shapes with Voigt
profiles. Helium, lightest noble gas perturber, exhibits
the effect of close collisional dephasing on
pressure broadened line profiles. Due to overlapping of atomic orbitals
the repulsive interaction dominates over attractive interaction
for collision diameter in the 3 to 4 Å range. In order to interpret
this type of linear polyatomic-monatomic collision phenomena the
Tipping-Herman potential has been chosen. Emphasis has been given to the
analysis of observed data to obtain information about interaction
potential, phase-shift and molecular constants. The results obtained
from detailed semi-classical model calculations are found to be in good
agreement with the observed data.
PACS: 42.62.Fi – Laser spectroscopy / 33.70.-w – Intensities and shapes of molecular spectral lines and bands / 33.70.Jg – Line and band widths, shapes, and shifts
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2001
