Quantum fluid density functional theory of time-dependent processes

A quantum fluid density functional theory has been developed through an amalgamation of the quantum fluid dynamics and the time-dependent density functional theory. It is used in studying typical time-dependent processes like ion–atom collisions and atom–field interaction. Temporal evolution of chemical reactivity parameters as electronegativity, hardness, entropy, and polarizability is monitored for a He atom in its ground and excited states interacting with an external electric field and an incoming proton. It is observed that these reactivity parameters either remain static or oscillate with the external field in the atom–field interaction case, whereas during the collision process, hardness and entropy maximize and polarizability minimizes for both the electronic states of the atom. The possibility of a quantum theory of motion within the purview of this quantum fluid density functional framework is also explored.