Multichannel quantum defect calculation of the phase lag in the coherent control of HI

Multichannel quantum defect theory (MQDT) is applied within a unified framework to compute the ionization and dissociation channel phases of HI. Our numerical results illustrate the mathematical origin of a channel phase within the MQDT formalism, and are consistent with the existing theory of this phenomenon, based on the collision formalism and with experimental measurements. The present study explains why previous MQDT calculations predicted that the channel phase vanishes identically. (C) 2001 American Institute of Physics.