Stark Effect of Vibration-Rotation Lines of Formaldehyde Observed by a 3.5 µm Laser

Abstract

A high resolution infrared spectroscopy of the Stark effect of H 2 CO and HDCO by using a magnetically tunable infrared-maser (laser) is reported. The output frequency of the He-Xe laser centered at 2850.6 cm -1 is tuned within ±6GHz to observe Stark patterns of vibration-rotation lines of formaldehyde in the electric field up to 44 kV/cm. Some of the lines have been assigned from their Stark effects. The observed Stark shift, K -type doubling, intensity change of the forbidden transition with the Stark field, and the assignment of lines are discussed in connection with the molecular constants of H 2 CO and HDCO.