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Electronic Structure of N 2 P 2 Four‐Membered Rings
Author(s) -
Escudero Daniel,
Frontera Antonio,
Streubel Rainer
Publication year - 2014
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201301233
Subject(s) - antibonding molecular orbital , singlet state , wave function , chemistry , atomic orbital , ab initio , molecular orbital , electronic structure , ground state , ab initio quantum chemistry methods , triplet state , character (mathematics) , computational chemistry , atomic physics , molecular physics , physics , molecule , electron , quantum mechanics , mathematics , geometry , excited state , organic chemistry
The biradicaloid character of the ground‐state structures of N 2 P 2 rings is studied by using the high‐level ab initio multiconfigurational CASPT2/CASSCF method. In order to obtain accurate descriptors, we combine two criteria: 1) singlet–triplet energy gaps and 2) relative values of the occupation numbers for bonding and antibonding orbitals associated with the radical sites. The singlet–triplet energy gaps, the occupation numbers of antibonding‐like orbitals, and the weights of the main configuration state functions (CSFs) of the ground‐state wavefunctions, that is, Ψ( 1 A 1 ), are used to derive the biradicaloid character that ranges from 10–15 %.