Floquet theory and complex quasivibrational energy formalism for intense field molecular photodissociation

A practical and nonperturbative method is presented for studying molecular photodissociation processes in the presence of (weak or intense) electromagnetic fields, using only square‐integrable (L2) functions. By means of the complex coordinate transformation and L2 discretization of the vibrational continua, the complex quasivibrational energies (QVE) of the Floquet Hamiltonian can be determined by standard non‐Hermitian eigenvalue analysis. The real parts of the QVE’s provide the ac Stark‐shifted vibronic energies, whereas the imaginary parts are related to the photodissociation transition rates. The theory is applied to the direct photodissociation of H+2(1sσg–2pσu) in both weak and strong fields.