title: Oscillator strengths, first-order properties, and nuclear gradients for local ADC(2).
abstract: We describe theory and implementation of oscillator strengths, orbital-relaxed first-order properties, and nuclear gradients for the local algebraic diagrammatic construction scheme through second order. The formalism is derived via time-dependent linear response theory based on a second-order unitary coupled cluster model. The implementation presented here is a modification of our previously developed algorithms for Laplace transform based local time-dependent coupled cluster linear response (CC2LR); the local approximations thus are state specific and adaptive. The symmetry of the Jacobian leads to considerable simplifications relative to the local CC2LR method; as a result, a gradient evaluation is about four times less expensive. Test calculations show that in geometry optimizations, usually very similar geometries are obtained as with the local CC2LR method (provided that a second-order method is applicable). As an exemplary application, we performed geometry optimizations on the low-lying singlet states of chlorophyllide a.
authors.affiliation: Institute of Physical and Theoretical Chemistry, University of Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Schütz
mesh_terms: D002735:Chlorophyllides / Q000737:chemistry*; D005415:Flavins / Q000737:chemistry; D006147:Guanine / Q000737:chemistry; D009991:Oscillometry; D011789:Quantum Theory; D014560:Urocanic Acid / Q000737:chemistry
chemical_list: C000605738:7-methyl-8-dimethylaminoisoalloxazine; D002735:Chlorophyllides; D005415:Flavins; C034388:chlorophyllide a; D006147:Guanine; D014560:Urocanic Acid