caa a22 4500 445865083 CHVBK 20180317145455.0 cr unu---uuuuu 170323e20111001xx s 000 0 eng 10.1140/epjd/e2011-20290-1 doi (NATIONALLICENCE)springer-10.1140/epjd/e2011-20290-1 On the actual nature of the anti-ferromagnetism shown by unrestricted calculations on conjugated hydrocarbon rings [Elektronische Daten] [E. San-Fabián, F. Moscardó] Unrestricted Hartree-Fock (UHF) calculations with spin-polarisation, plus Møller-Plesset (MP) perturbative corrections, have been applied to the study of the first four molecules of the family of n-acenes and also to the ground state of cyclobutadiene. The results are similar to those previously obtained for n-periacenes, which describe anti-ferromagnetic spin-polarised electronic structures. The projection to pure spin states gives results that recover the usual description of these molecules, i.e., non spin-polarised ground states. Extended coupled cluster calculations reinforce the projected results, also giving non spin-polarised ground states. EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg, 2011 San-Fabián E. Departamento de Química Física, Unidad Asociada del CSIC and Instituto Universitario de Materiales, Universidad de Alicante, San Vicente del Raspeig, 03690, Alicante, Spain aut Moscardó F. Departamento de Química Física, Unidad Asociada del CSIC and Instituto Universitario de Materiales, Universidad de Alicante, San Vicente del Raspeig, 03690, Alicante, Spain aut The European Physical Journal D Springer-Verlag 64/2-3(2011-10-01), 239-248 1434-6060 64:2-3<239 2011 64 10053 https://doi.org/10.1140/epjd/e2011-20290-1 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1140/epjd/e2011-20290-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- San-Fabián E. Departamento de Química Física, Unidad Asociada del CSIC and Instituto Universitario de Materiales, Universidad de Alicante, San Vicente del Raspeig, 03690, Alicante, Spain aut NATIONALLICENCE 700 1- Moscardó F. Departamento de Química Física, Unidad Asociada del CSIC and Instituto Universitario de Materiales, Universidad de Alicante, San Vicente del Raspeig, 03690, Alicante, Spain aut NATIONALLICENCE 773 0- The European Physical Journal D Springer-Verlag 64/2-3(2011-10-01), 239-248 1434-6060 64:2-3<239 2011 64 10053 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer