title: Pressure Dependence of Hydrogen-Bond Dynamics in Liquid Water Probed by Ultrafast Infrared Spectroscopy.
abstract: Clarifying the structure/dynamics relation of water hydrogen-bond network has been the aim of extensive research over many decades. By joining anvil cell high-pressure technology, femtosecond 2D infrared spectroscopy, and molecular dynamics simulations, we studied, for the first time, the spectral diffusion of the stretching frequency of an HOD impurity in liquid water as a function of pressure. Our experimental and simulation results concordantly demonstrate that the rate of spectral diffusion is almost insensitive to the applied pressure. This behavior is in contrast with the previously reported pressure-induced speed up of the orientational dynamics, which can be rationalized in terms of large angular jumps involving sudden switching between two hydrogen-bonded configurations. The different trend of the spectral diffusion can be, instead, inferred considering that the first solvation shell preserves the tetrahedral structure with pressure and the OD stretching frequency is only slight perturbed.
authors: LENS, European Laboratory for Nonlinear Spectroscopy , Via N. Carrara 1, I-50019 Sesto Fiorentino, Firenze, Italy.|Dipartimento di Chimica "Ugo Schiff" dell'Università degli Studi di Firenze , Via della Lastruccia 3, I-50019 Sesto Fiorentino, Firenze, Italy.|Istituto Nazionale di Ottica INO-CNR , Largo Fermi 6, 50125 Firenze, Italy.
authors: Andrea
authors: A
authors: Lapini
authors: Dipartimento di Chimica "Ugo Schiff" dell'Università degli Studi di Firenze , Via della Lastruccia 3, I-50019 Sesto Fiorentino, Firenze, Italy.
authors: Marco
authors: M
authors: Pagliai
authors: Istituto di Chimica dei Composti Organometallici ICCOM-CNR , Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy.
authors: Samuele
authors: S
authors: Fanetti
authors: LENS, European Laboratory for Nonlinear Spectroscopy , Via N. Carrara 1, I-50019 Sesto Fiorentino, Firenze, Italy.|Dipartimento di Chimica "Ugo Schiff" dell'Università degli Studi di Firenze , Via della Lastruccia 3, I-50019 Sesto Fiorentino, Firenze, Italy.
authors: Margherita
authors: M
authors: Citroni
authors: The Abdus Salam International Centre for Theoretical Physics (ICTP) , I-34151 Trieste, Italy.
authors: Sandro
authors: S
authors: Scandolo
authors: LENS, European Laboratory for Nonlinear Spectroscopy , Via N. Carrara 1, I-50019 Sesto Fiorentino, Firenze, Italy.|Dipartimento di Chimica "Ugo Schiff" dell'Università degli Studi di Firenze , Via della Lastruccia 3, I-50019 Sesto Fiorentino, Firenze, Italy.
authors: Roberto
authors: R
authors: Bini
authors: LENS, European Laboratory for Nonlinear Spectroscopy , Via N. Carrara 1, I-50019 Sesto Fiorentino, Firenze, Italy.|Dipartimento di Chimica "Ugo Schiff" dell'Università degli Studi di Firenze , Via della Lastruccia 3, I-50019 Sesto Fiorentino, Firenze, Italy.
authors: Roberto
authors: R
authors: Righini