Knowledge Bank

The $\nu 1$ (O-H stretch) and $\nu 3$ (O-Si stretch) bands of $HOSi+$ have been observed, and molecular constants have been determined for both the upper and lower states of both bands. There is good agreement between our constants, and those calculated by Botschwina and $Rosmus.1$ We employed the difference frequency laser system to observe the $\nu 1$ band, whose origin is approximately $3660cm-1$ and the diode laser to observe the $\nu 3$ band, whose origin is approximately $1130cm-1$. Both bands were observed in a hollow cathode discharge, with approximately 15 kHz discharge modulation. The initial detection of the ion was made by discharging $(CH3)3SiOH$ in a buffer of $H2$ and He, with high discharge current and water cooling. Later, it was discovered that better results could be obtained by mixing $SiH4$ and $N2O$ with either $H2$ or $H2$ and He, with dry-ice and methanol cooling. It was not possible to observe $HOSi+$ with mixtures of $SiH4$ and $H2O$. We have observed several lines of the $\nu 1$ band of $DOSi+$ around $2700cm-1$, but have no definitive assignment or molecular constants. This was produced in a similar manner to $HOSi+$, initially with ($CH3)3SiOD$ in a buffer of $D2$ and He, and subsequently with $SiH4$ in a buffer of $D2$ and He. Attempts to observe the $\nu 3$ band of $DOSi+$ were unsuccessful.