On the line shape of velocity modulation laser spectroscopy

The effect of pressure broadening on the line shape of velocity modulation laser spectroscopy is considered here, which is induced by the collisions o f the gas molecules. The old theory on velocity modulation spectroscopy is revised and new theory is setup to get the precise simulation of our experi mental spectrum. It has been shown that the new theory agrees with experime nts perfectly, and has potential applications in the investigation of the d ynamics of the collisions of molecular ions and obtaining more precisely re solved spectrum.