Background
The Hessian matrix (matrix of the second derivatives of the energy with respect to the atomic positions) and the vibrational frequencies of a system are important in the DFT calculations.
It is necessary to implement the functionality for ABACUS.
Background
The Hessian matrix (matrix of the second derivatives of the energy with respect to the atomic positions) and the vibrational frequencies of a system are important in the DFT calculations.
It is necessary to implement the functionality for ABACUS.