The response of water re-solvating a charge-transfer dye (deprotonated Coumarin 343) after photoexcitation has been measured by means of transient THz spectroscopy. Two steps of increasing THz absorption are observed, a first ∼10 ps step on the time scale of Debye relaxation of bulk water and a much slower step on a 3.9 ns time scale, the latter of which reflecting heating of the bulk solution upon electronic relaxation of the dye molecules from the S1 back into the S0 state. As an additional reference experiment, the hydroxyl vibration of water has been excited directly by a short IR pulse, establishing that the THz signal measures an elevated temperature within ∼1 ps. This result shows that the first step upon dye excitation (10 ps) is not limited by the response time of the THz signal; it rather reflects the reorientation of water molecules in the solvation layer. The apparent discrepancy between the relatively slow reorientation time and the general notion that water is among the fastest solvents with a solvation time in the sub-picosecond regime is discussed. Furthermore, non-equilibrium molecular dynamics simulations have been performed, revealing a close-to-quantitative agreement with experiment, which allows one to disentangle the contribution of heating to the overall THz response from that of water orientation.
Skip Nav Destination
Aqueous solvation from the water perspective
Article navigation
21 June 2018
Research Article|
June 19 2018
Aqueous solvation from the water perspective
Special Collection:
JCP Editors' Choice 2018
Saima Ahmed;
Saima Ahmed
Department of Chemistry, University of Zurich
, Zurich, Switzerland
Search for other works by this author on:
Andrea Pasti;
Andrea Pasti
Department of Chemistry, University of Zurich
, Zurich, Switzerland
Search for other works by this author on:
Ricardo J. Fernández-Terán
;
Ricardo J. Fernández-Terán
Department of Chemistry, University of Zurich
, Zurich, Switzerland
Search for other works by this author on:
Gustavo Ciardi;
Gustavo Ciardi
Department of Chemistry, University of Zurich
, Zurich, Switzerland
Search for other works by this author on:
Andrey Shalit;
Andrey Shalit
Department of Chemistry, University of Zurich
, Zurich, Switzerland
Search for other works by this author on:
Peter Hamm
Peter Hamm
Department of Chemistry, University of Zurich
, Zurich, Switzerland
Search for other works by this author on:
J. Chem. Phys. 148, 234505 (2018)
Article history
Received:
April 10 2018
Accepted:
May 16 2018
Citation
Saima Ahmed, Andrea Pasti, Ricardo J. Fernández-Terán, Gustavo Ciardi, Andrey Shalit, Peter Hamm; Aqueous solvation from the water perspective. J. Chem. Phys. 21 June 2018; 148 (23): 234505. https://doi.org/10.1063/1.5034225
Download citation file:
Sign in
Don't already have an account? Register
Sign In
You could not be signed in. Please check your credentials and make sure you have an active account and try again.
Sign in via your Institution
Sign in via your InstitutionPay-Per-View Access
$40.00
Citing articles via
Related Content
Network analysis of proton transfer in liquid water
J. Chem. Phys. (June 2014)
Nonlinear effects on solvation dynamics in simple mixtures
J. Chem. Phys. (December 2006)
Solvation dynamics study of 3‐aminophthalimide in n‐butanol solution at different temperatures
J. Chem. Phys. (December 1996)
Solvation dynamics study of 4‐amino‐N‐methyl‐phthalimide in n‐alcohol solutions
J. Chem. Phys. (April 1996)