Simultaneous determination of absorption cross sections and decay rate constants by quantitative laser mass spectrometry

A method is described that allows the simultaneous measurement of the transition cross sections between the molecular states involved in a multiphoton process and the decay rate constants for the intermediate levels involved. The technique is based on the quantitative determination of the multiphoton ionization efficiency as a function of the laser intensity applied. From these values the cross sections and rate constants are extracted by an algorithm using multiple non-linear regression. Several examples are discussed and compared to values obtained with conventional techniques.