Nonradiative relaxation mechanisms of the elusive silole molecule

• Published in: Physical chemistry chemical physics : PCCP 2021-12, Vol.23 (46), p.26561-26574
• Main Authors: de Castro Araujo Valente, Daniel, Borges, Itamar, Cardozo, Thiago Messias
• Format: Article
• Language: English
• Subjects: Absorption spectra; Coupling (molecular); Electronic structure; Equations of motion; Molecular dynamics; Optoelectronics; Potential energy; Switches
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d1cp03803f

Silole derivatives have been extensively employed for developing organic optoelectronics, but few studies focused on the photophysical properties of the silole molecule. In this work, we investigate these properties by computing the absorption spectra and performing nonadiabatic molecular dynamics of silole employing the algebraic diagrammatic construction [ADC(2)] and extended multi-state XMS-CASPT2 ab initio electronic structure methods. For vertical excitations and excited state optimizations, the equation of motion coupled-cluster singles and doubles (EOM-CCSD) was also used. The nuclear ensemble and the fewest-switches surface hopping molecular dynamics methods coupled with the first two high-level electronic structure methods were applied to probe the relaxation mechanisms of silole. We could reproduce the experimental first absorption maximum value and found an ultrafast relaxation process occurring exclusively through ring-puckering distortions without breaking ring bonds or hydrogen elimination. Minimum energy conical intersection optimizations were carried out and potential energy curves, including triplet states, were calculated to further elucidate the relaxation process of silole. The relaxation of excited-state silole was studied using XMS-CASPT2 and ADC(2) static and dynamic calculations, with ring puckering playing a major role.