Electronic Transitions Responsible for C60+ Diffuse Interstellar Bands

Aleksandr O Lykhin; Seyedsaeid Ahmadvand; Sergey A Varganov

doi:10.1021/acs.jpclett.8b03534

Electronic Transitions Responsible for C₆₀⁺ Diffuse Interstellar Bands

J Phys Chem Lett. 2019 Jan 3;10(1):115-120. doi: 10.1021/acs.jpclett.8b03534. Epub 2018 Dec 21.

Authors

Aleksandr O Lykhin¹, Seyedsaeid Ahmadvand¹, Sergey A Varganov¹

Affiliation

¹ Department of Chemistry , University of Nevada, Reno , 1664 North Virginia Street , Reno , Nevada 89557-0216 , United States.

PMID: 30560674
DOI: 10.1021/acs.jpclett.8b03534

Abstract

Diffuse interstellar bands (DIBs) are puzzling absorption features believed to contain critical information about molecular evolution in space. Despite the fact that C₆₀⁺ recently became the first confirmed carrier of several DIBs, the nature of the corresponding transitions is not understood. Using electronic structure methods, we show that the two strong C₆₀⁺ DIBs cannot be explained by electronic transitions to the two different excited ² E_{1 g} states or the two spin-orbit components of the lowest ² E_{1 g} state, as suggested before. We argue that the strong DIBs at 9632 and 9577 Å correspond to the cold excitations from the non-Franck-Condon region of the ground electronic state to the two components of the lowest ² E_{1 g} state split by Jahn-Teller distortion. The weak DIBs at 9428 and 9365 Å are assigned to the first vibronic transitions involving the low-energy vibrational modes and components of the lowest ² E_{1 g} electronic state.