I have just started writing a program using Hartree-Fock approximation. I have constructed my Hamiltonian (4 by 4 matrix, number of states=4) and found eigenvalues and eigenvectors(4 eigenvectors with length 4, and 4 corresponding energies).
Then I found the eigenvectors related to the last 3 min energy (Number of particles=3) to replace the previous guessed eigenvectors with (so that I can construct the new hamiltonian and find the new min energy and see if it is converging).
My question is how should I calculate the min total energy (in each step of SCF method)? Should it be the average of 3 min energies I am getting in each iteration? Or should I just save the smallest energy among those 3 min energies I am getting in each Iteration?
If my question is not clear let me write it in this way and tell you what I have done and what my question is:
1- NOS=4 (Number of states)
2- NOP=3 (Number of particles)
3- Basis Function is built (4 * 1 vector)
4- Coefficient matrix (3 * 4 Matrix)
5- Hamiltonian(4 * 4 MAtrix)
6- Eigenvectors=(I have got four vectors (4*1 length)) & Eigenvalues: (4 numbers)
7-Choosing the 3 eigenvector related to the 3 minimum energy (and constructing the 3*4 matrix to put instead of number 4(coefficient matrix)), and recalculate the Hamiltonian...(SCF method)
???8-saving the min energy? (I don't know what should I do here? cause I have 3 values for energy related to the chosen eigenvectors. Should I save the meanvalue of them as the total minimum energy?)