{"about":{"site":"https://codewithpapers.app","non_affiliation":"Code with Papers and Syntology are not affiliated with, endorsed by, or sponsored by Papers with Code, Meta, or the pwc-archive mirror.","licence":"CC BY-SA 4.0","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","attribution":"https://codewithpapers.app/attribution","modified":"archive material modified by Syntology; see the attribution page"},"url":"/paper/mp2-based-composite-extrapolation-schemes-can","title":"MP2-based composite extrapolation schemes can predict core-ionization energies for first-row elements with coupled-cluster level accuracy","arxiv_id":"2403.06364","date":"2024-03-11","proceeding":null,"authors":["Anton Morgunov","Henry K. Tran","Oinam Romesh Meitei","Yu-Che Chien","Troy Van Voorhis"],"abstract":"X-ray photoelectron spectroscopy (XPS) measures core-electron binding energies (CEBEs) to reveal element-specific insights into chemical environment and bonding. Accurate theoretical CEBE prediction aids XPS interpretation but requires proper modeling of orbital relaxation and electron correlation upon core-ionization. This work systematically investigates basis set selection for extrapolation to the complete basis set (CBS) limit of CEBEs from $\\Delta$MP2 and $\\Delta$CC energies across 94 K-edges in diverse organic molecules. We demonstrate that an alternative composite scheme using $\\Delta$MP2 in a large basis corrected by $\\Delta$CC-$\\Delta$MP2 difference in a small basis can quantitatively recover optimally extrapolated $\\Delta$CC CEBEs within 0.02 eV. Unlike $\\Delta$CC, MP2 calculations do not suffer from convergence issues and are computationally cheaper, and, thus, the composite $\\Delta$MP2/$\\Delta$CC scheme balances accuracy and cost, overcoming limitations of solely using either method. We conclude by providing a comprehensive analysis of the choice of small and large basis sets for the composite schemes and provide practical recommendations for highly accurate (within 0.10-0.15 eV MAE) ab initio prediction of XPS spectra.","url_abs":"https://arxiv.org/abs/2403.06364v1","url_pdf":"https://arxiv.org/pdf/2403.06364v1.pdf","source":{"archive":"pwc-archive (Hugging Face), CC BY-SA 4.0","snapshot":"2025-07-28","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","row_kind":"links_only","authors_date_abstract":"arXiv metadata, CC0 1.0 (https://info.arxiv.org/help/license), from the Kaggle arXiv metadata snapshot of 2026-09-12"},"code_links":[{"paper_slug":"mp2-based-composite-extrapolation-schemes-can","repo_url":"https://github.com/anmorgunov/cebe_prediction","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":1,"framework":"none","reach":null}],"tasks":[],"methods":[],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"atlas_url":null,"mcp":null,"developers":"https://syntology.ai/developers"},"arxiv_metadata":null,"syntology_extracted_results":null}