title: Determining the strengths of hydrogen bonds in solid-state ammonia and urea: insight from periodic DFT calculations.
abstract: Plane-wave density functional theory has been applied to determine the strengths of hydrogen bonds in the phase I crystal structures of ammonia and urea. For ammonia, each component of the trifurcated hydrogen bond has been found to be almost as strong as a standard N-H.N interaction, and for urea the strengths of the two different N-H.O interactions have been determined by a quantum mechanical technique for the first time.
authors.affiliation: School of Chemistry, University of Edinburgh The King's Buildings, West Mains Road Edinburgh, EH9 3JJ, UK. c.morrison@ed.ac.uk
authors.forename: Carole A
authors.initials: CA
authors.lastname: Morrison
authors.forename: Muhammad M
authors.initials: MM
authors.lastname: Siddick
mesh_terms: D000641:Ammonia / Q000737:chemistry*; D018360:Crystallography, X-Ray; D019281:Dimerization; D006860:Hydrogen Bonding; D008432:Mathematical Computing; D008958:Models, Molecular; D011789:Quantum Theory; D013816:Thermodynamics; D014508:Urea / Q000737:chemistry*
chemical_list: D000641:Ammonia; D014508:Urea