The Hartree-Fock equations are, in their simplest form, solved in an iterative way, starting with a guess for the
coefficients C_{i\alpha} . We label the coefficients as C_{i\alpha}^{(n)} , where the subscript n stands for iteration n .
To set up the algorithm we can proceed as follows:
- We start with a guess C_{i\alpha}^{(0)}=\delta_{i,\alpha} . Alternatively, we could have used random starting values as long as the vectors are normalized. Another possibility is to give states below the Fermi level a larger weight.
- The Hartree-Fock matrix simplifies then to (assuming that the coefficients C_{i\alpha} are real)
\hat{h}_{\alpha\beta}^{HF}=\epsilon_{\alpha}\delta_{\alpha,\beta}+
\sum_{j = 1}^A\sum_{\gamma\delta} C_{j\gamma}^{(0)}C_{j\delta}^{(0)}\langle \alpha\gamma|\hat{v}|\beta\delta\rangle_{AS}.