ArticleIUCrJ2014
Hirshfeld atom refinement.
Article in IUCrJ, 2014. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 103 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
103 citing papers in PubMed, 291 citations in OpenAlex.
- A crystalline uranium Fischer-type carbyne.Nature chemistry · 2026Article
- Are crystal structures getting better? A temporal and elemental analysis of the Cambridge Structural Database.Acta crystallographica. Section C, Structural chemistry · 2026Article
- Application of electrostatic and multi-layer embedding in Hirshfeld atom refinements: a cost-effective approach for approximating bulk effects in crystalline environments.Journal of applied crystallography · 2026Article
- Metformindiium dibromide.IUCrData · 2026Article
- Hydride and Seek: Comparing Crystallographic Hydride Placement Techniques with an Open-Shell Cobalt Complex.ACS central science · 2026Article
- Article
- Periodic Hirshfeld Atom Refinement.The journal of physical chemistry letters · 2026Article
- Linear-scaling aspherical crystallographic refinement of proteins: a case study for crambin and rubredoxin.IUCrJ · 2026Article
- Interplay between geometry, electron density, and polarizability of the controversial drug atoxyl in crystal and biological environments.RSC advances · 2025Article
- Role of restraints on hydrogen atoms in Hirshfeld atom refinement: the case of tri-aspartic acid trihydrate.Acta crystallographica Section B, Structural science, crystal engineering and materials · 2025Article
- Improving Polymeric Structures with Hirshfeld Atom Refinement: A Study on MOFs and COFs.ACS materials Au · 2025Article
- Weak yet directional: supramolecular interactions of thiols unravelled by quantum crystallography.Chemical science · 2025Article
- Benchmarking crystal structure refinement: A systematic study on Hirshfeld atom refinement.Structural dynamics (Melville, N.Y.) · 2025Article
- SISYPHOS: An automatic procedure for the serial refinement of single-crystal diffraction data in Olex2.Structural dynamics (Melville, N.Y.) · 2025Article
- Strain-Release Driven Arsenium Ion Bond Insertion.Angewandte Chemie (International ed. in English) · 2025Article
- Inversion of the X-ray restrained wavefunction equations: a first step towards the development of exchange-correlation functionals based on X-ray data.Journal of applied crystallography · 2025Article
- Article
- Benchmarking quantum chemical methods with X-ray structures via structure-specific restraints.IUCrJ · 2025Article
- Article
- Synthesis and quantum crystallographic evaluation of WYLID: YLID's red rival.Journal of applied crystallography · 2025Article
43 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors at 4 institutions in 4 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Hirshfeld atom refinement (HAR) is a method which determines structural parameters from single-crystal X-ray diffraction data by using an aspherical atom partitioning of tailor-made ab initio quantum mechanical molecular electron densities without any further approximation. Here the original HAR method is extended by implementing an iterative procedure of successive cycles of electron density calculations, Hirshfeld atom scattering factor calculations and structural least-squares refinements, repeated until convergence. The importance of this iterative procedure is illustrated via the example of crystalline ammonia. The new HAR method is then applied to X-ray diffraction data of the dipeptide Gly-l-Ala measured at 12, 50, 100, 150, 220 and 295 K, using Hartree-Fock and BLYP density functional theory electron densities and three different basis sets. All positions and anisotropic displacement parameters (ADPs) are freely refined without constraints or restraints - even those for hydrogen atoms. The results are systematically compared with those from neutron diffraction experiments at the temperatures 12, 50, 150 and 295 K. Although non-hydrogen-atom ADPs differ by up to three combined standard uncertainties (csu's), all other structural parameters agree within less than 2 csu's. Using our best calculations (BLYP/cc-pVTZ, recommended for organic molecules), the accuracy of determining bond lengths involving hydrogen atoms from HAR is better than 0.009 Å for temperatures of 150 K or below; for hydrogen-atom ADPs it is better than 0.006 Å(2) as judged from the mean absolute X-ray minus neutron differences. These results are among the best ever obtained. Remarkably, the precision of determining bond lengths and ADPs for the hydrogen atoms from the HAR procedure is comparable with that from the neutron measurements - an outcome which is obtained with a routinely achievable resolution of the X-ray data of 0.65 Å.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.