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Updated: Jan 25, 2026

Direct Imaging of Laser-driven Ultrafast Molecular Rotation
Published on: February 4, 2017
Ultrafast Vibrational Cooling Inside of a Molecular Container
Yaroslav V Aulin1, Mengdi Liu1, Piotr Piotrowiak1
1Department of Chemistry , Rutgers University-Newark , 73 Warren Street , Newark , New Jersey 07102 , United States.
Abstract:
Vibrational cooling of azulene encapsulated in a hemicarcerand molecular container was studied by pump-probe spectroscopy. Within 1.5 ps of excitation of azulene to the S1 state, rapid internal conversion through a conical intersection leads to the formation of a vibrationally hot (∼1080 K) ground state, the subsequent cooling of which can be monitored by tracking the evolution of the red-shifted hot band at the edge of the ground-state absorption. It was found that the cooling of the hot S0 state of azulene in the host-guest complex (hemicarceplex) is 2-4 times faster than that in common organic solvents. Such large acceleration points to a high density of matching vibrational modes and efficient mechanical coupling between the guest and the host. The experimental observations were fully corroborated by the results of molecular dynamics simulations.
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