Pressure dependence of the ac stark shifts in nitric oxide: resonant multiphoton spectroscopy without space charge

Measurements of ac Stark shifts and broadening have been made on several multiphoton resonant rotational-vibronic levels in nitric oxide (NO). The levels and laser wavelengths are carefully chosen so that the number of ions produced can be kept low and the complication due to space charge can be avoided. It is found that the ac Stark effects are independent of the pressure.