Theoretical study of the excitation spectrum of azomethane

Theoretical study of the absorption spectrum of trans-azomethane (AZM) was presented. Coupled-Cluster type methods (EOMEE-CCSD, CC3), ADC(2) as well as TDDFT/B3LYP calculations with different basis sets were used to obtain the vertical excitation energies and transition moments. The absorption spectrum was simulated by the Linear Vibronic Coupling method by Köppel et al. [Adv. Chem. Phys. 57 (1984) 59] and by semi-classical procedure. Our investigations show that complicated vibronic spectra such as the one of AZM can be well simulated and analyzed by these theoretical techniques.