An atom is the smallest constituent unit of ordinary matter that has the properties of a chemical element.
The atomic number or proton number (symbol Z) of a chemical element is the number of protons found in the nucleus of an atom.
In particle physics, the Dirac equation is a relativistic wave equation derived by British physicist Paul Dirac in 1928.
Dover Publications, also known as Dover Books, is an American book publisher founded in 1941 by Hayward Cirker and his wife, Blanche.
The electron is a subatomic particle, symbol or, whose electric charge is negative one elementary charge.
The hartree (symbol: Eh or Ha), also known as the Hartree energy, is the atomic unit of energy, named after the British physicist Douglas Hartree.
In quantum mechanics, the principal quantum number (symbolized n) is one of four quantum numbers which are assigned to all electrons in an atom to describe that electron's state.
Quantum chemistry is a branch of chemistry whose primary focus is the application of quantum mechanics in physical models and experiments of chemical systems.
Slater-type orbitals (STOs) are functions used as atomic orbitals in the linear combination of atomic orbitals molecular orbital method.
STO-nG basis sets are minimal basis sets, where n primitive Gaussian orbitals are fitted to a single Slater-type orbital (STO).