SEARCH Articles Figures Tables Electron density Hellmann-Feynman theorem Expectation values Hellmann-Feynman theorem Hellmann-Feynman Hellmann-Feynman Theorem Time-Dependent Hellmann-Feynman and virial theorems Hellmann-Feynman electrostatic theorem Hellmann-Feynman theorem Hamiltonian Hellmann-Feynman theorem electronic kinetic energy Hellmann-Feynman theorem force Hellmann-Feynman theorem matrix Hellmann-Feynman theorem nuclear motion Schrodinger equation Hellmann-Feynman theorem theory Hellmann—Feynman theorem generalized Second Quantization and Hellmann-Feynman Theorem The Hellmann-Feynman Theorem The Hellmann-Feynman Theorem for Approximate Wavefunctions