{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T21:24:53Z","timestamp":1788470693504,"version":"build-2803163510"},"reference-count":72,"publisher":"American Chemical Society (ACS)","issue":"4","license":[{"start":{"date-parts":[[2020,3,5]],"date-time":"2020-03-05T00:00:00Z","timestamp":1583366400000},"content-version":"vor","delay-in-days":21,"URL":"https:\/\/pubs.acs.org\/page\/policy\/authorchoice_ccby_termsofuse.html"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2020,4,14]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>We present a protocol based on unitary transformations of molecular orbitals to reduce the number of nonvanishing coefficients of spin-adapted configuration interaction expansions. Methods that exploit the sparsity of the Hamiltonian matrix and compactness of its eigensolutions, such as the full configuration interaction quantum Monte Carlo (FCIQMC) algorithm in its spin-adapted implementation, are well suited to this protocol. The wave function compression resulting from this approach is particularly attractive for antiferromagnetically coupled polynuclear spin systems, such as transition-metal cubanes in biocatalysis, and Mott and charge-transfer insulators in solid-state physics. Active space configuration interaction calculations on N2 and CN\u2013 at various bond lengths, the stretched square N4 compounds, the chromium dimer, and a [Fe2S2]2\u2013 model system are presented as a proof-of-concept. For the Cr2 case, large and intermediate bond distances are discussed, showing that the approach is effective in cases where static and dynamic correlations are equally important. The [Fe2S2]2\u2013 case shows the general applicability of the method.<\/jats:p>","DOI":"10.1021\/acs.jctc.9b01013","type":"journal-article","created":{"date-parts":[[2020,2,13]],"date-time":"2020-02-13T13:37:11Z","timestamp":1581601031000},"page":"2202-2215","source":"Crossref","is-referenced-by-count":56,"title":["Compression of Spin-Adapted Multiconfigurational Wave\nFunctions in Exchange-Coupled Polynuclear Spin Systems"],"prefix":"10.1021","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3666-3880","authenticated-orcid":true,"given":"Giovanni","family":"Li Manni","sequence":"first","affiliation":[{"name":"Max-Planck-Institut fu\u0308r Festko\u0308rperforschung , Heisenbergstra\u00dfe 1 , ,","place":["Stuttgart, Germany, 70569"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Werner","family":"Dobrautz","sequence":"additional","affiliation":[{"name":"Max-Planck-Institut fu\u0308r Festko\u0308rperforschung , Heisenbergstra\u00dfe 1 , ,","place":["Stuttgart, Germany, 70569"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ali","family":"Alavi","sequence":"additional","affiliation":[{"name":"Max-Planck-Institut fu\u0308r Festko\u0308rperforschung , Heisenbergstra\u00dfe 1 , ,","place":["Stuttgart, Germany, 70569"]},{"name":"University of Cambridge , , Lensfield Road , ,","place":["Cambridge, United Kingdom, CB2 1EW"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"316","published-online":{"date-parts":[[2020,2,13]]},"reference":[{"key":"2026090316592908600_cit1","unstructured":"Bogdanov, N. 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