X-ray, energetic photon, and electron irradiation can ionize and electronically excite target atoms and molecules. These excitations undergo complicated relaxation and energy-transfer processes that ultimately determine the manifold system responses to the deposited excess energy. In weakly bound...

The accurate description of excited vibronic states is important for modeling a wide range of photoinduced processes. The nuclear–electronic orbital (NEO) approach, which treats specified protons on the same level as the electrons, can describe excited electronic–protonic states. Herein the...