title: Chemical shift computations on a crystallographic basis: some reflections and comments.
abstract: Computations for chemical shifts of molecular organic compounds using the gauge-including projector augmented wave method and the NMR-CASTEP code are reviewed. The methods are briefly introduced, and some general aspects involving the sources of uncertainty in the results are explored. The limitations are outlined. Successful applications of the computations to problems of interpretation of NMR results are discussed and the range of areas in which useful information is obtained is illustrated by examples. The particular value of the computations for comparing shifts between resonances where the same chemical site is involved is emphasised. Such cases arise for shifts between different crystallographically independent molecules of the same chemical species, between polymorphs and for shift anisotropies and asymmetries.
authors.affiliation: Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, UK. r.k.harris@durham.ac.uk.
authors.forename: Robin K
authors.initials: RK
authors.lastname: Harris
authors.forename: Paul
authors.initials: P
authors.lastname: Hodgkinson
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Pickard
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Yates
authors.forename: Vadim
authors.initials: V
authors.lastname: Zorin
mesh_terms: D000465:Algorithms; D000667:Ampicillin / Q000737:chemistry; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D005466:Fluorocarbons / Q000737:chemistry; D005480:Flurbiprofen / Q000737:chemistry; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008320:Maltose / Q000737:chemistry; D008956:Models, Chemical; D008968:Molecular Conformation; D009281:Naphthalenes / Q000737:chemistry; D013726:Terbutaline / Q000737:chemistry; D013739:Testosterone / Q000737:chemistry; D014297:Trimethylsilyl Compounds / Q000737:chemistry
chemical_list: D005466:Fluorocarbons; D009281:Naphthalenes; D014297:Trimethylsilyl Compounds; C523241:octafluoronaphthalene; D013739:Testosterone; C073196:tetramethylsilane; D005480:Flurbiprofen; D008320:Maltose; D000667:Ampicillin; D013726:Terbutaline