The document discusses the Schrodinger equation, which is a partial differential equation that uses the concepts of energy conservation and kinetic and potential energy to describe the behavior of electrons bound to an atom's nucleus. It has both time-dependent and time-independent forms. The time-dependent equation describes how a quantum system evolves over time, while the time-independent equation predicts stationary states. The Schrodinger equation is widely used in physics and chemistry to study atomic structure and find allowed energy levels of quantum systems.