title: Arbitrary-Order Density Functional Response Theory from Automatic Differentiation.
abstract: We demonstrate how the functional derivatives appearing in perturbative time-dependent density functional theory can be calculated using automatic differentiation. The approach starts from a computer implementation of the exchange-correlation energy functional, from which arbitrary-order derivatives are generated automatically. Automatic differentiation is shown to provide an accurate, general, and efficient implementation of higher-order exchange-correlation functional derivatives that is easy to maintain. When used in combination with an arbitrary-order response solver, the methodology allows us to generate arbitrary-order response functions from time-dependent density functional theory.
authors.affiliation: Division of Theoretical Chemistry, Amsterdam Center for Multiscale Modeling, VU University - Faculty of Sciences, De Boelelaan 1083, NL-1081 HV Amsterdam, The Netherlands, and Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø, N-9037 Tromsø, Norway.
authors.forename: Ulf
authors.initials: U
authors.lastname: Ekström
authors.affiliation: Division of Theoretical Chemistry, Amsterdam Center for Multiscale Modeling, VU University - Faculty of Sciences, De Boelelaan 1083, NL-1081 HV Amsterdam, The Netherlands, and Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø, N-9037 Tromsø, Norway.
authors.forename: Lucas
authors.initials: L
authors.lastname: Visscher
authors.affiliation: Division of Theoretical Chemistry, Amsterdam Center for Multiscale Modeling, VU University - Faculty of Sciences, De Boelelaan 1083, NL-1081 HV Amsterdam, The Netherlands, and Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø, N-9037 Tromsø, Norway.
authors.forename: Radovan
authors.initials: R
authors.lastname: Bast
authors.affiliation: Division of Theoretical Chemistry, Amsterdam Center for Multiscale Modeling, VU University - Faculty of Sciences, De Boelelaan 1083, NL-1081 HV Amsterdam, The Netherlands, and Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø, N-9037 Tromsø, Norway.
authors.forename: Andreas J
authors.initials: AJ
authors.lastname: Thorvaldsen
authors.affiliation: Division of Theoretical Chemistry, Amsterdam Center for Multiscale Modeling, VU University - Faculty of Sciences, De Boelelaan 1083, NL-1081 HV Amsterdam, The Netherlands, and Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø, N-9037 Tromsø, Norway.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Ruud