By 1928, the idea of a molecular orbital had been advanced by Robert Mulliken, who was i… 展开

We introduce the atomic orbitals φ m ( r ) {\displaystyle \varphi _{m}(\mathbf {r} )} , which are eigenfunctions of the Hamiltonian H a t {\displaystyle H_{\rm {at}}} of a single isolated atom. W… 展开

As mentioned before the values of the β m {\displaystyle \beta _{m}} -matrix elements are not so large in comparison with the ionization energy because the potentials of neighboring ato… 展开

Bloch functions describe the electronic states in a periodic crystal lattice. Bloch functions can be represented as a Fourier series 1. ψ m ( k , r ) = 1 N ∑ n a m ( R n , r ) e i k ⋅ R n , {\dis… 展开

Modern explanations of electronic structure like t-J model and Hubbard model are based on tight binding model. Tight binding can be understood by working under a second quantizat… 展开