INFRARED SPECTROSCOPY OF AN $H_{2} / O_{2}$ DISCHARGE: II - THE $H_{2}O^{+}$ ION

$^{1}$ B. M. Dinelli, M. W. Crofton, and T. Oka, J. Mol. Spectrosc. 127, 1-11 (1988). $^{2}$ This result was also observed by Urban's group at Bonn; private communication - H. Solka.Author Institution: Department of Chemistry and Department of Astronomy and Astrophysics, The University of Chicago; Istituto di Spettroscopia Molecolare, Via de'Castagnoli 1During a thorough investigation of an $H_{2} / O_{2}$ glow discharge, conditions which favored the formation of the $H2O+$ ion over the more abundant $H_{3}O^{+}$ ion were discovered. A high resolution tunable infrared laser ( color center laser ) spectrometer along with high sensitivity velocity modulation detection was used to study an AC glow discharge between $3100 - 3600 cm^{-1}$. The $\nu_{3}$ fundamental of the $H_{2}O^{+}$ ion which had been identified earlier1 was observed using 50 mtorr $H_{2}$, 50 mtorr $O_{2}$ and 10 torr He. But, it was discovered that the S/N increased considerably in just a pure He discharge, owing to a small water impurity in the He $tank^{2}$. This also had the effect of reducing, in fact almost eliminating completely, the signals due to $H_{3}O^{+}$. This greatly helped in the identification of many more transitions from the $v_{3}$, and also made possible the identification of the $v_{1}$ fundamental. The alchemy of the discharge along with assignment of the $v_{1}$ and $v_{3}$ of the $H_{2}O^{+}$ ion will be presented