Assessment of TD-DFT methods and of various spin scaled CIS(D) and CC2 versions for the treatment of low-lying valence excitations of large organic dyes

Abstract

We present an extension of our previously published benchmark set for low-lying valence transitions of large organic dyes [L. Goerigk, Phys. Chem. Chem. Phys. 11, 4611 (2009)]. The new set comprises in total 12 molecules, including two charged species and one with a clear charge-transfer transition. Our previous study on TD-DFT methods is repeated for the new test set with a larger basis set. Additionally, we want to shed light on different spin-scaled variants of the configuration interaction singles with perturbative doubles correction [CIS(D)] and the approximate coupled cluster singles and doubles method (CC2). Particularly for CIS(D) we want to clarify, which of the proposed versions ca..