High-Performance Computational Photochemistry and Spectroscopy

Introduction

The future of modern sustainable technologies lies in the exploitation of solar energy and in harnessing the sun’s practically infinite energy. For fundamental as well as target-oriented research in this direction, computer simulations of the ongoing photochemical processes and electronic spectroscopy of the underlying molecular materials are indispensable.

Challenges in Current Methods

While for smaller molecules, computational photochemistry can nowadays provide highly accurate results and reliable predictions, the limit in applicable molecular system size is quickly reached. The obtained results often come with an unpredictable error requiring a posteriori validation.

Limitations

Indeed, we are lacking efficient and sufficiently accurate and reliable excited-state ab initio methods reaching out for organic molecular systems with more than 500 second-row atoms.

Project Goals

In HIPERCOPS, we aim at closing this gap by deriving highly efficient and genuinely parallel ab initio methods for the calculation of:

1. Excited electronic states
2. Electron-detached states
3. Electron-attached states

These methods will be designed for execution on modern high-performance computer architectures, whose full potential is impossible to leverage by existing standard quantum chemical program packages.

Methodology

To address this problem, we choose the algebraic-diagrammatic construction (ADC) family of methods, since these schemes offer clear advantages, including:

• Numerical stability
• Ease of use
• Predictable accuracy

We will exploit novel genuinely parallel concepts and solution strategies for ADC schemes to enable them for HPC architectures.

Expected Outcomes

Our developed methods and resulting easy-to-use software will thus push the boundaries of accurate and predictable computational photochemistry to unprecedented molecular system sizes. This will enable and promote research in areas such as:

• Functional optoelectronic devices and photovoltaics
• Molecular solar thermal energy conversion
• Solar-driven nanomachines

Ultimately, this project aims towards efficient molecular harnessing of sunlight.