Rump session by Jarvist Moore Frost

Quantum corrosion – tight-binding with open boundaries

Rump session chaired by
Jarvist Moore Frost
King’s College London, UK

Wednesday 10th of July, from 5pm onwards
(the session continues until the chair closes it, but not later than 7pm)

Corrosion is an electrochemical process with very long time and length scales. This requires the use of approximate electronic structure techniques. In an ideal world we would directly simulate and measure the double-layer, include explicit electrolyte, be able to simulate variable pH.

Open-boundary conditions are required to run simulations at a potential difference. A self-consistent and quantum-mechanical method is required, to include the charge transfer and polarisation required by electrochemistry.

From our perspective, using a tight-binding minimal basis is the obvious approach to take [1]. This requires simultaneous method development, and construction of validated models.

After a short introduction to polarisable-ion tight-binding [2], and hairy probe open boundary conditions [3], we will open to general discussion.

Three problems which we plan to discuss are:

  • Molecules in the liquid state need to have their molecular dynamics simulated, while at the same time allowing for chemistry (electron transfer, bond breaking) to occur. Polarisable ion tight binding is one possible method.
  • How to provide a voltage across the simulation. This requires electron open boundaries, to some level of theory. We will discuss Hairy Probes – a computationally efficient way to impose these.
  • Longer range electrostatics. The spatial range of electric potential goes well beyond the limit even of tight-binding. What is the best way to embed an electrochemical simulation?

We encourage contributions from others working on getting to these large length and time scales, particularly if using a minimal atomic basis for the calculations. The aim of this rump session is to discuss method development, rather than particular materials or applications. If you would like to prepare materials to present, please get in touch with the chair to coordinate timings.