Knowledge Bank

The $H24-0$ S(1) and S(0) lines have been measured at various pressures in the range 200 Torr to 3000 Torr, using a ring dye laser, at an optical path of 5.984 kilometers. Initial analysis shows a possible non-linear density (pressure"") shift of the 4 -- 0 S(1) line at low densities; this is in contrast to the usual straight line $extrapolation^{1-3}$. The experimental set-up also revealed an interesting interference effect in White-type multiple path absorption cells. A new method for multiple beam injection in a White cell will also be described. A measurement of the 5--0 S(1) line is being attempted. $^{1}$ A.R.W. McKellar, The Significance of Pressure Shifts for the Interpretation of $H2$ Quadrupole Lines in Planetary Spectra"", ICARUS 22, 212--219 (1974). $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$ Susan Lynn Bragg. An Experimental Study of the Vibrational-Rotational Spectrum of Molecular Hydrogen:, Ph. D. Dissertation, Washington University (1981). $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}$K. Narahari Rao, M. E. Mickelson, and J. T. Trauger, J. Mol. Structure, 217, 85-98 (1990).""