# Hellmann–Feynman theorem

> theorem that relates the derivative of the total energy with respect to a parameter, to the expectation value of the derivative of the Hamiltonian with respect to that same parameter

**Wikidata**: [Q906809](https://www.wikidata.org/wiki/Q906809)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Hellmann–Feynman_theorem)  
**Source**: https://4ort.xyz/entity/hellmann-feynman-theorem


## References

1. Freebase Data Dumps. 2013