title: The hydrogen-bond collective dynamics in liquid methanol.
abstract: The relatively simple molecular structure of hydrogen-bonded (HB) systems is often belied by their exceptionally complex thermodynamic and microscopic behaviour. For this reason, after a thorough experimental, computational and theoretical scrutiny, the dynamics of molecules in HB systems still eludes a comprehensive understanding. Aiming at shedding some insight into this topic, we jointly used neutron Brillouin scattering and molecular dynamics simulations to probe the dynamics of a prototypical hydrogen-bonded alcohol, liquid methanol. The comparison with the most thoroughly investigated HB system, liquid water, pinpoints common behaviours of their THz microscopic dynamics, thereby providing additional information on the role of HB dynamics in these two systems. This study demonstrates that the dynamic behaviour of methanol is much richer than what so far known, and prompts us to establish striking analogies with the features of liquid and supercooled water. In particular, based on the strong differences between the structural properties of the two systems, our results suggest that the assignment of some dynamical properties to the tetrahedral character of water structure should be questioned. We finally highlight the similarities between the characteristic decay times of the time correlation function, as obtained from our data and the mean lifetime of hydrogen bond known in literature.
authors.affiliation: Università di Firenze, Dipartimento di Fisica, Sesto Fiorentino, I-50019, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Bellissima
authors.affiliation: Istituto Italiano di Tecnologia, Center for Life Nanoscience, Roma, I-00161, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: De Panfilis
authors.affiliation: Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, Sesto Fiorentino, I-50019, Italy.
authors.forename: Ubaldo
authors.initials: U
authors.lastname: Bafile
authors.affiliation: Brookhaven National Laboratory, National Synchrotron Light Source II, Upton, New York 11973, USA.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Cunsolo
authors.affiliation: Institut Laue-Langevin, Grenoble, F-38042, France.
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: González
authors.affiliation: Università di Firenze, Dipartimento di Fisica, Sesto Fiorentino, I-50019, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Guarini
authors.affiliation: Consiglio Nazionale delle Ricerche, Istituto Officina dei Materiali, Operative Group in Grenoble, F-38042, France.
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Formisano