Knowledge Bank

A commercial color center laser was used to observe RF-IR double resonance signals in low pressure gas phase samples. Initial measurements have been made on HCN. $\Delta J=0,\Delta M=\pm 1$ transitions were observed in the 000 and 001 levels and $\Delta l=2,\Delta J=0,\Delta M=0$ transitions were obtained in the 010 and 011 states. RF transitions ranging from 10 to 750 MHz were observed by monitoring infrared absorption. Instrumental linewidth is determined by pressure broadening and is less than 0.5 MHz. 100 KHz RF amplitude modulation permitted changes in IR absorption as small as 1 part in $107$ to be detected. Stark effect measurements produced $\mu (011)=2.976(1)D$ and $q(011)=227.99(3)$ MHz.