Determination of line strengths for selected transitions in the v2 band relative to the v1 and v5 bands of H2CO

The spectral line strengths in the v2 band of H2CO (segments spanning 1720-1780cm−1) have been determined relative to two sets of spectral line groups in the v1 and v5 band, (∼2830cm−1) using tunable diode laser spectroscopy. Simultaneous detection using a dual-diode instrument with a 150m absorption cell was employed to assure identical H2CO column density for the two spectral regions. The results in the selected regions of this study are in good agreement with the line positions and the relative intensities specified in an unpublished complete line listing for the v2 band prepared by Linda Brown (see full text for reference). Based upon measurements of individual groups of spectral lines in the P, Q and R branches, the absolute band strength has been determined to be 76±5kmmol−1.