TY - JOUR
T1 - Vibronic Coupling Drives the Ultrafast Internal Conversion in a Functionalized Free-Base Porphyrin
AU - Petropoulos, Vasilis
AU - Rukin, Pavel S.
AU - Quintela, Frank
AU - Russo, Mattia
AU - Moretti, Luca
AU - Moore, Ana
AU - Moore, Thomas
AU - Gust, Devens
AU - Prezzi, Deborah
AU - Scholes, Gregory D.
AU - Molinari, Elisa
AU - Cerullo, Giulio
AU - Troiani, Filippo
AU - Rozzi, Carlo A.
AU - Maiuri, Margherita
N1 - Publisher Copyright:
© 2024 American Chemical Society.
PY - 2024/4/25
Y1 - 2024/4/25
N2 - Internal conversion (IC) is a common radiationless transition in polyatomic molecules. Theory predicts that molecular vibrations assist IC between excited states, and ultrafast experiments can provide insight into their structure-function relationship. Here we elucidate the dynamics of the vibrational modes driving the IC process within the Q band of a functionalized porphyrin molecule. Through a combination of ultrafast multidimensional spectroscopies and theoretical modeling, we observe a 60 fs Qy-Qx IC and demonstrate that it is driven by the interplay among multiple high-frequency modes. Notably, we identify 1510 cm-1 as the leading tuning mode that brings the porphyrin to an optimal geometry for energy surface crossing. By employing coherent wave packet analysis, we highlight a set of short-lived vibrations (1200-1400 cm-1), promoting the IC within ≈60 fs. Furthermore, we identify one coupling mode (1350 cm-1) that is responsible for vibronic mixing within the Q states. Our findings indicate that porphyrin-core functionalization modulates IC effectively, offering new opportunities in photocatalysis and optoelectronics.
AB - Internal conversion (IC) is a common radiationless transition in polyatomic molecules. Theory predicts that molecular vibrations assist IC between excited states, and ultrafast experiments can provide insight into their structure-function relationship. Here we elucidate the dynamics of the vibrational modes driving the IC process within the Q band of a functionalized porphyrin molecule. Through a combination of ultrafast multidimensional spectroscopies and theoretical modeling, we observe a 60 fs Qy-Qx IC and demonstrate that it is driven by the interplay among multiple high-frequency modes. Notably, we identify 1510 cm-1 as the leading tuning mode that brings the porphyrin to an optimal geometry for energy surface crossing. By employing coherent wave packet analysis, we highlight a set of short-lived vibrations (1200-1400 cm-1), promoting the IC within ≈60 fs. Furthermore, we identify one coupling mode (1350 cm-1) that is responsible for vibronic mixing within the Q states. Our findings indicate that porphyrin-core functionalization modulates IC effectively, offering new opportunities in photocatalysis and optoelectronics.
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U2 - 10.1021/acs.jpclett.4c00372
DO - 10.1021/acs.jpclett.4c00372
M3 - Article
C2 - 38630018
AN - SCOPUS:85190744605
SN - 1948-7185
VL - 15
SP - 4461
EP - 4467
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
IS - 16
ER -