In a recent paper of this journal (Tajti;; Szalay. J. Chem. Theory Comput. 2019, 15, 5523), we
have shown that failures of the CC2 method to describe Rydberg excited states as well as
potential energy surfaces of certain valence excited states can be cured by spin-component
scaled (SCS) versions SCS-CC2 and SOS-CC2 to a large extent. In this paper, the related
and popular second-order algebraic diagrammatic construction (ADC (2)) method and its
SCS variants are inspected with the previously established methodology. The results reflect …

Benchmark calculations with the Spin-Component-Scaled CC2 variants SCS-CC2 and SOS-
CC2 are presented for the electronically excited valence and Rydberg states of small-and
medium-sized molecules. Besides the vertical excitation energies and excited state
gradients, the potential energy surfaces are also investigated via scans following the forces
that act in the Franck–Condon region. The results are compared to the regular CC2 ones, as
well as higher level methods CCSD, CCSD (T)(a)*, and CCSDT. The results indicate that a …