Atto fridays seminar series – Friday 07/11, 3pm UK time, online

This is to let you know that there is an Atto Fridays seminar this Friday, 07/11/2025, at 3pm UK time, online. Our speaker is Professor Graham Worth (UCL) and he will talk about Simulating Photo-Excited Processes using Grids and Gaussian Wavepackets

Registration is free at
https://us02web.zoom.us/webinar/register/WN_NZHnO6i7Sb2IJYLA6z9V9g

Alternatively you can watch the live-streaming on YouTube at https://www.youtube.com/@QuantumBattles
(The live chat is open for subscribers)

Below you will find an abstract and a brief bio of the speaker.
----
Title: Simulating Photo-Excited Processes using Grids and Gaussian Wavepackets

Abstract:
Simulating the time-evolution of molecular systems after photo-excitation is
complicated by the need to include a manifold of excited electronic states.
These states are coupled by so-called non-adiabatic coupling due to
the interaction of the electronic and nuclear motion which
makes the system highly quantum mechanical. As a result it is necessary to solve
the time-dependent Schroedinger Equation (TDSE) for reliable results.
To solve the TDSE, however, is a hard computational problem due to the
exponential scaling of required resources with system size. The
multi-configuration time-dependent Hartree (MCTDH) method provides a suitable
algorithm that efficiently contracts the wavefunction to make it manageable
for many degrees of freedom [1]. Such simulations can provide a full description
of the evolving system, and it is possible to include the excitation by light
pulses to obtain a spectroscopic signal that can be directly compared to
experiments, such as REMPI spectra [2]. It is also possible to study the
coherences induced in a system by a set of pulses [3]. These simulations,
however, are constrained by the need for an analytic Hamiltonian, which is
usually unable to describe long-range motions. For this, methods such as
the direct dynamics variational multi-configuration Gaussian (DD-vMCG)
method are required that calculate the potential surfaces on-the-fly and so
allow a flexible description of the longe-time molecular response[4].

[1] Beck et al Phys. Rep. (00) 324: 1
[2] Dey et al PCCP (24) 26: 3451
[3] Dey et al PRL (22) 129: 173203
[4] Spinlove et al Farad. Discuss. (18) 212: 191

Short Bio:

Graham Worth is a Professor of Computational Chemistry at University College London.
He did his PhD at Oxford University developing Free Energy Perturbation simulations
for condensed phase thermodynamics. He then did postdoctoral work at the EMBL and
Heidelberg University, where he started working on the MCTDH method for the quantum
dynamics simulations of polyatomic molecules. He is now a lead developer of the
Quantics suite for quantum dynamics, which includes a range of algoritjms to solve
the time-dependent Schroedinger Equation, including MCTDH and Gaussian wavepacket
methods. His main interests are simulating non-adiabatic dynamics and photo-excited
processes. Present development work focuses on generating potential surfaces on-the-fly
using direct dynamics.

All welcome!

Carla Faria (on behalf of the Atto Fridays team)