Excited-State Studies of Polyacenes: A Comparative Picture Using EOMCCSD, CR-EOMCCSD(T), Range-Separated (LR/RT)-TDDFT, TD-PM3, and TD-ZINDO

• DOI: 10.1021/ct2005165
• Publication Date: 2011-10-03T12:22:44Z
• Authors: K. Lopata; R. Reslan; M. Kowalska; D. Neuhauser; N. Govind; K. Kowalski
• Keywords: ZINDO; Coupled cluster; Acene

The low-lying excited states (La and Lb) of polyacenes from naphthalene to heptacene (N = 2-7) are studied using various time-dependent computational approaches. We perform high-level excited-state calculations equation motion coupled cluster with singles doubles (EOMCCSD) completely renormalized singles, doubles, perturbative triples (CR-EOMCCSD(T)) use these results evaluate the performance range-separated exchange-correlation functionals within linear-response (LR) real-time (RT) density functional theories (TDDFT). As has been reported recently, we find that family addresses well-documented TDDFT failures in describing singlet a large extent as about accurate EOMCCSD on average. Real-time visualization shows state charged densities consistent predictions perimeter free electron orbital (PFEO) model. This corresponds particle-on-a-ring confinement, which leads well-known red-shift excitations acene length. also semiempirical methods like TD-PM3 TD-ZINDO, capable handling very systems. Once reparametrized match CR-EOMCCSD(T) results, TD-ZINDO becomes roughly TDDFT, opens door modeling systems such molecular assemblies.