The time duration of quantum processes has challenged physicists for 80 years. To address this question and other fundamental questions in quantum mechanics, we are studying quantum transition path time distributions Preliminary work has already led to the discovery of new quantum phenomena, such as localization beyond the Heisenberg limits or shorter transit times for longer paths.
One may identify two central challenges facing theoretical chemistry at the beginning of the 21st century. Even with present day powerful computers, we do not know how to solve for the quantum dynamics of large systems. A viable Monte Carlo based quantum mechanical method which could be used as readily as classical dynamics programs is not available. A second aspect of this challenge is related to the force field. Even if one were to develop a basis set method for the dynamics, one would still need the force field. When using classical mechanics this is readily available. However, in quantum mechanics, for basis set methods one needs a global potential energy surface and this is too expensive.
Experimentally it has been observed that when heavy atoms such as Ar are scattered from metal surfaces, their angular distribution is a double peaked one. It has been well understood that the two peaks are related to the classical rainbow angles.
Theory of heavy atom quantum diffraction
Quantum diffraction of heavy atoms has been observed in many instances in the past, albeit without a deep theoretical analysis.
The generalized time dependent perturbation theory developed for the real time SCIVR methodology can also be used within a thermodynamic context.