%0 Online Multimedia
%A Soler, Jordi
%A Sarkar, Rudraditya
%A Boggio-Pasqua, Martial
%D 2019
%T Theoretical Rationalization of the Dual Photophysical Behavior of C60+
%U https://acs.figshare.com/articles/media/Theoretical_Rationalization_of_the_Dual_Photophysical_Behavior_of_C_sub_60_sub_sup_sup_/7749167
%R 10.1021/acs.jpca.8b11761.s002
%2 https://acs.figshare.com/ndownloader/files/14417897
%K near-IR laser excitation populates
%K nonradiative decay
%K nonradiative decay channels
%K radiationless decay channel
%K radiative decay
%K D 0
%K D 5
%K UV light excitation
%K near-IR excitation
%K Dual Photophysical Behavior
%K state D 5
%K ground state
%K DIB
%K sloped conical intersection
%K C 60
%K TD-DFT
%K neon matrixes exhibits
%X Interest
in fullerenes has been renewed recently in astrophysics
as a consequence of their detection in circumstellar environments.
In particular, C60+ was detected in the diffuse
interstellar medium and its presence has been related to some diffuse
interstellar bands (DIBs) whose origin was previously unknown. A single
recent laboratory experiment (J. Phys. Chem. A 2017, 121, 7356–7361) shows that upon
laser excitation at 785 nm, C60+ in neon matrixes
exhibits a radiative decay at 965 nm, while UV photoexcitation does
not lead to any significant luminescence. To rationalize this original
dual photophysical behavior, we have performed time-dependent density
functional theory (TD-DFT) calculations on C60+ to investigate the potential energy surfaces of the relevant electronic
states, completed by the simulations of vibrationally resolved absorption
and emission spectra. The proposed photophysical pathways shed light
on the experimental measurements: The near-IR laser excitation populates
the 11th doublet excited state (D11) that decays to the
lowest first bright excited state D5, from which photoluminescence
is predicted. Indeed, D5 is largely separated from the
lower electronic states (D0–D4). Thus,
D5 behaves effectively as the first excited state, while
the D0–D4 set of states act as the electronic
ground state. In addition, there are no low-lying conical intersections
between D5 and lower excited states energetically accessible
upon near-IR excitation that can provide efficient nonradiative decay
channels for this state, leaving radiative decay as the most likely
deactivation pathway. However, a sloped conical intersection between
D5 and D4 was located around 2.9 eV above D0. While it is too high in energy to be accessible upon near-IR
excitation, it provides a funnel for efficient nonradiative decay
down to the ground state (D0) accessible upon UV light
excitation. Thus, the photophysics of C60+ is
controlled by the ability to access this funnel: Upon near-IR excitation,
the system fluoresces because the funnel for nonradiative decay cannot
be reached, while UV irradiation provides a different route by opening
up a radiationless decay channel via this funnel, accounting for the
absence of fluorescence.
%I ACS Publications