# The Electronic Response Function in an Ab Initio Electronic Structure Calculation

Speaker | Vincent Sacksteder (Royal Hollow University London) |

Venue | P/T/111 |

Time | 4pm on 6th March 2017 |

Many calculations of electronic structure approximate the interactions between electrons using a local density functional. Here we describe our efforts to take the CASTEP ab initio DFT code beyond local density functionals, to a more accurate treatment of electronic interactions. The key new physics which we are adding is the electronic response function, a quantity which describes the system's response to a small perturbation. This is an explicitly dynamic quantity, and contrasts with DFT's focus on steady-state equilibrium physics.

We plan several applications of the electronic response function: (A) calculations of spectra in the GW approximation, (B) MP2 and RPA total energies and geometry optimization, (C) quicker, more robust calculations of magnetic systems, and (D) calculation of magnetic excitations and charge wave excitations.