An analytic theory of photodissociation of linear symmetric polyatomic molecules

An analytic theory of the direct dissociation of linear symmetric polyatomic molecules is developed. The theory is based on a power series expansion of the excited-state potential surface. It provides an analytical expression for the Franck–Condon integrals. Simple formula for the dissociation cross section as a function of wave number is given. To illustrate the immediate applicability of this approach, the formula is used to calculate the profiles of the absorption spectra of dimethylated metal alkyl molecules; good agreement with the measured spectra is seen, and molecular constants with clear physical meanings can be extracted from the curve fitting.