A new scheme for controlling photodissociation through preparation of a variationally optimized linear superposition of field-free vibrational eigenstates is applied for selective control of IBr photodissociation. The dependence of IBr photodissociation on various field parameters and initial conditions is explored. In a broad range of field parameters, the product yield is shown to increase considerably when a photolysis pulse is applied to the variationally optimized linear combination as opposed to photolysis of IBr with the entire population in a single vibrational level. The frequency, intensity, and phase dependence of this enhancement is explored for both CW and Gaussian pulses.