ARCHER2 Calendar January 2023

Acetylene Molecule subject to intense ultra-fast laser pulse, time evolution of electron probability, sound

Dale Hughes, Queen's University Belfast, Physics

The movie is a straightforward plot of electron density, derived from substantial Time-Dependent Density Functional Theory calculations carried out in recent months on ARCHER2. The sound is derived from the oscillating electric field induced by the laser interaction, and is unprocessed. In this simulation, we have directed a 1 femtosecond(fs) ultraviolet laser pulse along the molecular axis of a single Acetylene molecule, and allowed the time evolution to continue for around 1000fs. We immediately see significant oscillation, and at around 500fs we begin to hear a new oscillation, termed a dipole instability, that has increased in magnitude exponentially since the end of the initial pulse (1fs) until it is of comparable magnitude to the initial pulse. It reaches its peak as the population inversion induced by the initial pulse ends, as the electron excited by the pulse recombines with its hole. This dipole instability is the current subject of our work with ARCHER2.

This image was published on the January page of the ARCHER2 2023 printed calendar.