Premium
Oriented Nonspherical Atoms in Crystals Deduced from X‐Ray Scattering Data
Author(s) -
Miller Lance L.,
Jacobson Robert A.,
Ruedenberg Klaus,
Niu Jier,
Schwarz W. H. Eugen
Publication year - 2001
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/1522-2675(20010613)84:6<1907::aid-hlca1907>3.0.co;2-b
Subject(s) - chemistry , degenerate energy levels , valence (chemistry) , anthracene , crystallography , molecule , x ray , scattering , crystal (programming language) , molecular physics , atomic physics , computational chemistry , quantum mechanics , physics , organic chemistry , computer science , programming language
A crystallographic pro‐molecule/pro‐crystal model is described that goes beyond the standard reference model, which explicitly contains only numerically determined atomic positions and thermal vibrational smearings, while leaving all other information lumped together in a so‐called deformation density. The new model includes further explicit parameters that identify valence‐orbital orientations and occupancies of degenerate or near‐degenerate atomic ground states in crystals. A method is described for extracting this additional information as well from X‐ray data by least‐mean‐squares refinements. It is applied to the experimental data sets of three organic molecules: 9‐( tert ‐butyl)anthracene, tetrafluoroterephthalonitrile, and 1,2,3‐triazine. The electronic structure inferences are discussed.