# Accurate description of intermolecular interaction energies from extended random phase approximation

The goal of the project is to develop a new theoretical method that would predict energy of covalently and noncovalently bonded molecules. The method is derived from the equations of motion of Rowe. The excitation operator utilized in the equations of motion includes single and some double excitations. By analogy to the random phase approximation approach (RPA) the method is called extended random phase approximation (ERPA). ERPA equations allow for finding both the ground state energy of a system and its excitation energies at modest computational. Since the method is capable of capturing electron correlation effects of a different nature it describes very different phenomena like bond breaking and molecular interactions, all at the cost of the RPA methods.