Collision-induced spectra of molecular hydrogen in the first overtone region at 77,201 and 295 K

Van Nostrand, Edward (1983) Collision-induced spectra of molecular hydrogen in the first overtone region at 77,201 and 295 K. Masters thesis, Memorial University of Newfoundland.

[img] [English] PDF (Migrated (PDF/A Conversion) from original format: (application/pdf)) - Accepted Version
Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission.

Download (55MB)
  • [img] [English] PDF - Accepted Version
    Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission.
    (Original Version)

Abstract

The collision-induced absorption spectra of molecular hydrogen in its first overtone region has been recorded with a 2 m high-pressure low-temperature absorption cell for gas densities up to 940 amagat at 77, 201 and 295 K. The observed spectra in the main region consists of pure overtone (i.e. Δv=2) single transitions O₂ (J), Q₂ (J) and S₂ (J), pure overtone double transitions Q₂ (J) + Q₀ (J) and Q₂ (J) + S₀ (J) and double fundamental (i.e. Δv=1) transitions O₁ (J) + Q₁ (J). Q₁ (J) + Q₁ (J) and Q₁ (J) + S₁ (J). In addition, double transitions S₂ (J) + S₀ (J) (corresponding to a first overtone vibrational-rotational transition in one molecule and a simultaneous pure rotational transition in its collision partner) and S₁ (J) + S₁ (J) (corresponding to a simultaneous fundamental vibrational-rotational transition in each molecule of the colliding pair) have been observed for the first time for normal hydrogen at 77 K. These S + S transitions arise entirely from the contribution to the intermolecular interaction by the anisotropy of the polarizability of molecule in the quadrupole field of its collision partner. -- An analysis of the observed profiles on the basis of the theory of the quadrupole induction mechanism has been attempted using a symmetrized modified dispersion lineshape (with an extra fourth power term in the denominator) and the available matrix elements of the quadrupole moment, polarizability and anisotropy of the polarizability of the H₂ molecule; it is found that the calculated intensities of the transitions involving Δv=2 are somewhat too high. However, a reduction of the Δv=2 quadrupole moment matrix elements by a factor of 0.68 is found to give a good agreement between the calculated absorption profiles and the experimental profiles at all the three experimental temperatures. Pressure narrowing of the SΔᵥ (J) + SΔᵥ (J) transitions in the first overtone region for pure gas densities in the range 640 - 940 amagst at 77 K has been clearly observed for the first time. -- A reanalysis of the absorption profiles of the S₁ (J) + S₀ (J) transitions of the fundamental band of H₂ at 77 K obtained earlier in our laboratory is also reported.

Item Type: Thesis (Masters)
URI: http://research.library.mun.ca/id/eprint/7615
Item ID: 7615
Additional Information: Bibliography: leaves 102-105.
Department(s): Science, Faculty of > Physics and Physical Oceanography
Date: 1983
Date Type: Submission
Library of Congress Subject Heading: Hydrogen--Spectra

Actions (login required)

View Item View Item

Downloads

Downloads per month over the past year

View more statistics