INVERSION OF ABSORPTION SPECTRAL DATA FOR RELAXATION MATRIX DETERMINATION - I - APPLICATION TO LINE MIXING IN THE 106[-000-OVERTONE TRANSITION OF HCN

A new method of extracting the relaxation matrix directly from absorpt ion spectral data is formulated and applied to R-branch line mixing in HCN. The formulation makes use of a general iterative inversion algor ithm based upon first-order sensitivity analysis and Tikhonov regulari zation. The recovered relaxation matrices describe line mixing much be tter than those derived from the fitting laws currently in use, and th e inversion algorithm usually converges within just three iterations. This formulation presents the first known method for extracting the im aginary, off-diagonal elements of the relaxation matrix. (C) 1998 Amer ican Institute of Physics.