A TIME-DEPENDENT GOLDEN-RULE WAVE PACKET CALCULATION FOR VIBRATIONAL PREDISSOCIATION OF D2HF

Calculations of the total and partial decay widths are presented for the vibrational predissociation of D2HF. The calculation is done for the total angular momentum J = 0 of the molecule and for the dissociation process D2HF(upsilon = 1) --> D2(upsilon = 1) + HF(upsilon = 0), which is the dominant decaying channel. A time-dependent wave packet approach in the golden rule approximation is employed in the numerical calculation for the decay widths. Our computed total and partial decay widths are in good agreement with those from a time-independent scattering calculation. The time-dependent golden rule wave packet method, which does not solve coupled channel scattering equations, offers an efficient alternative to the time-independent scattering method for computing the decay widths in vibrational predissociation for relatively large molecules. The total time of propagation required in the golden rule wave packet calculation is determined by the duration time of the final state interaction between the fragments on the vibrationally deexcited adiabatic potential surface. This interpretation clearly explains the fact that only a short time is needed in our wave packet propagation, regardless of how long the lifetime of the predissociating state may be.