Periodic Reporting for period 4 - CC4SOL (Towards chemical accuracy in computational materials science)
Berichtszeitraum: 2022-01-01 bis 2023-06-30
The present project explored ideas and developed new methods that reduce the computational cost of highly accurate coupled cluster theories employed in computational materials science simulations of periodic crystals and surfaces. The demand and prospects for these methods are excellent given that they can predict atomization- and reaction energies in a wide range of solids and molecules with chemical accuracy (≈43 meV). This project successfully reduced their computational cost by developing more efficient representations and convergence acceleration techniques for the calculation of the underlying many-electron wavefunctions and expectation values. In addition to the methodological developments, the study of challenging solid-state physics and chemistry problems formed an important part of this project. We employed the newly developed methods directly to investigate molecular adsorption and reactions on surface and pressure-driven solid-solid phase transitions.
In addition to the methodological developments, several more applied research projects have been carried out and resulted in published research articles. These applied projects focus on solid-solid phase transitions, molecular adsorption on surfaces and defects. Two articles about solid-solid phase transitions have been published in PRB 98, 134108 (2018) and npj Computational Materials 5, 1-6 (2019). In these studies, we have computed enthalpy differences of different carbon and boron nitride allotropes as well as high pressure phases of hydrogen that can be used to predict temperature- pressure phase diagrams. In addition, we have performed highly accurate ab initio investigations on the interaction between single water molecules and sheets of h-BN and graphene. The obtained findings have been published in PRX 8, 021043 (2018) and JPCL 3, 358 (2019). Furthermore, an investigation of dissociative hydrogen adsorption on Silicon has been published in JCP 149, 244105 (2018). A recent work focused on the study of defects in solids and is published in PRB 108, 115125 (2023). The reported applications have clearly demonstrated the potential and high accuracy of the investigated coupled cluster methods for computational materials science. We hope that these findings will serve as useful reference values in future studies and help to improve the accuracy and efficiency of widely used methods used in computational materials science in general.
In the final phase of this project the developed computer codes used to perform massive parallel coupled cluster theory calculations have been published and made freely available at https://github.com/cc4s. Alongside the computer code, we have published a documentation describing the code and how it can be used.