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Are localized broken symmetry solutions acceptable in molecular calculations?
Author(s) -
Goscinski Osvaldo
Publication year - 2009
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560280807
Subject(s) - symmetry (geometry) , excited state , physics , wave function , yield (engineering) , circular symmetry , explicit symmetry breaking , symmetry breaking , function (biology) , core (optical fiber) , theoretical physics , quantum mechanics , spontaneous symmetry breaking , mathematics , geometry , thermodynamics , optics , evolutionary biology , biology
The question of localized versus nonlocalized broken symmetry core‐hole and low‐lying excited states is reviewed with particular emphasis on the role of the overall symmetry. The broken‐symmetry solutions, which yield for core‐ionization very good results for the energy, if symmetrized give a splitting and perhaps a worse energy. It is argued that when the splitting is smaller than the experimental resolution the appropriate description of the physical state is not a wave function, but a density matrix (statistical ensemble) of broken‐symmetry states with correct overall symmetry.