Simulations of anisotropic vibrations in ice induced by a laser

Sammanfattning

Systems of atoms have their kinetic energy distributed between three parts: translation, rotation and vibration. These are usually kept about the same following a Maxwell distribution, but under certain circumstances, this equilibrium might break. This would lead to, for example, ice melting anisotropically. In this report, it was determined if ice experiences anisotropic movement when it is exposed to a laser pulse in the form of an electric field. If ice experiences anisotropy, a time frame from when ice moves anisotropically until the movement is isotropic was established. This was done through molecular dynamics simulations using the GROMACS program on a system of solid ice crystals with multiple levels of field strengths. The simulations showed that anisotropy clearly exist in a solid ice structure when affected by the pulse, no matter if it's melting or not. The time period for when anisotropy existed in the ice was normally until the system had melted, which is about a minimum of 40 ps.