On the physical mechanisms underlying single molecule dynamics in simple liquids
Abstract
Physical arguments and comparisons with published experimental data suggest that in simple liquids: (i) single-molecule-scale viscous forces are produced by temperature-dependent London dispersion forces, (ii) viscosity decay with increasing temperature reflects electron cloud compression and attendant suppression of electron screening, produced by increased nuclear agitation, and (iii) temperature-dependent self-diffusion is driven by a narrow band of phonon frequencies lying at the low-frequency end of the solid-state-like phonon spectrum. The results suggest that collision-induced electron cloud distortion plays a decisive role in single molecule dynamics: (i) electron cloud compression produces short-lived repulsive states and single molecule, self-diffusive hops, while (ii) shear-induced distortion generates viscosity and single-molecule-scale viscous drag. The results provide new insight into nonequilibrium molecular dynamics in nonpolar, nonmetallic liquids.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 28, 2021
- Source ID
- 10.1038/s41598-021-82112-8
Entities
People
- Jerry Dahlberg
- Peter T. Tkacik
- Russell G. Keanini
Organizations
- Office of Naval Research