Atoms and molecules in a confined environment

Abstract

Soon after the discovery of quantum mechanics, several model systems were developed. One of them, perhaps the simplest, was the particle-in-a-box problem. Solutions of this model confined system revealed several aspects of a quantum mechanical system. The more confined a particle in space is, the higher is its energy. The uncertainty in its position and the uncertainty in its momentum are in keeping with the Heisenberg’s uncertainty principle. That a quantum mechanical system could have a nonzero energy even at 0 K was its consequence.