TIME-DEPENDENT R-MATRIX THEORY OF MULTIPHOTON PROCESSES

A new time-dependent R-matrix theory of multiphoton processes is descr ibed which can be applied to an arbitrary many-electron atom. The theo ry is complementary to the R-matrix Floquet theory developed by Burke, Francken and Joachain (1991 J. Phys. B: At. Mel. Opt. Phys. 24 761) e nabling processes involving higher laser field intensities and shorter laser purses to be treated. The new theory is illustrated by analysin g the multiphoton ionization of a charged particle bound initially in a one-dimensional potential well where the results are compared with a n independent R-matrix Floquet calculation.