Matrix Hamiltonian??? 1. The problem statement, all variables and given/known data I have two non-identical spin 1/2 particles, which have vector magnetic moments S_1 and S_2. The interaction energy (Hamiltonian) is given by a constant times the dot product of S_1 and S_2. There is no external field present. I need to find the eigenstates and eigenenergies, which I could easily do if the Hamiltonian was given as a matrix. Is there a way to write this H as a matrix or is there perhaps another way to find the eigen-items? Thanks so much for any input!!