Vibrational excitation of ${\mathrm{H}}_2$ by electron impact: An energy-dependent vibrational-frame-transformation approach

An energy-dependent rovibrational-frame-transformation method, combined with the multichannel quantum-defect theory, has been applied to study the vibrational excitations of ${\mathrm{H}}_2$ by electron collision in the energy range below 5 eV. A class of nonadiabatic effects resulting from large collision time delay has been accounted for. Using a special set of short-range Born-Oppenheimer eigenstates, this approach does not explicitly introduce electron-molecule compound states. We show that the body-frame quantum-defect function ${\mathrm{\mu }}_{\mathit{l}=1\mathrm{}}$(ɛ,R), containing the information about the dynamical coupling of the incident electron and the molecular target, is all one needs to describe the scattering properties of the system.