Questions tagged [variational-principle]

For questions related to variational methods in matter modeling.

Filter by
Sorted by
Tagged with
7
votes
1answer
101 views

How is the error in a wavefunction related to the error in energy?

While studying the variational method in McQuarrie's Quantum Chemistry, I came across the following problem: to relate the difference between an approximation $\phi$ and the exact ground-state wave ...
24
votes
1answer
186 views

How do you calculate the “true” chemical potential in classical density functional theory?

In classical density functional theory, one traditionally calculates the chemical potential by taking the variational derivative, \begin{equation} \mu_{i} = \frac{\delta F}{\delta \rho_{i}}\tag{1} \...
15
votes
1answer
111 views

How does a complete basis set remove Pulay forces/stress?

When finding nuclear forces for the true electronic wavefunction, thanks to the Hellmann-Feynman theorem we only need to consider explicit derivatives with respect to the nuclear coordinates $\mathbf{...
21
votes
1answer
84 views

QMC calculation of the equation of state of metals

Is diffusion/variational quantum Monte Carlo applicable to the calculation of the athermal (zero temperature, no zero point energy) equation of state of metals including electronic correlation? For ...