# Anomalous behavior of dispersion of longitudinal and transverse collective excitations in water

## TL;DR

This paper investigates the unusual behavior of collective excitation frequencies in water, revealing anomalies in their dependence on temperature and density, contrasting with typical liquid behavior.

## Contribution

It provides new insights into the anomalous dispersion behavior of water's collective excitations along different thermodynamic paths.

## Key findings

- Longitudinal excitation frequency shows anomalous temperature dependence along an isochore.
- Dependence of excitation frequencies on density along an isotherm is minimal or negligible.
- Behavior differs from that observed in ordinary liquids.

## Abstract

We study the dependence of the excitation frequency of water along an isochore and an isotherm crossing the region of density anomaly. We have shown that the frequency of the longitudinal excitations demonstrated anomalous dependence on temperature along the isochore. At the same time the dependence for both longitudinal and transverse excitation frequencies on density along the isotherm are very modest or even negligible in rather wide range of densities. This kind of behavior also seems anomalous in comparison with the ordinary liquids.