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International
Tables for Crystallography Volume G Definition and exchange of crystallographic data Edited by J. R. Hester and B. McMahon © International Union of Crystallography 2026 |
International Tables for Crystallography (2026). Vol. G. Early view chapter
https://doi.org/10.1107/97809553602060001011 Chapter 4.2 Core dictionary (coreCIF) |
Core dictionary version 3.3.0
_geom_hbond.distance_HA
Name:_geom_hbond.distance_HA
Aliases:
_geom_hbond_distance_HA
_geom_hbond.dist_HA
Definition:
The distance between the hydrogen and acceptor atoms at the listed
sites and accompanying symmetry operation codes.
Type: Real
Units: angstroms
The permitted range is 0.0 → infinity
Evaluation method:
with g as geom_hbond
l,s = g.atom_site_label_A, g.site_symmetry_A
a_pos = SymEquiv(s, _atom_site[l].fract_xyz)
a_pos = _atom_sites_Cartn_transform.matrix * a_pos
l,s = g.atom_site_label_H,g.site_symmetry_H
h_pos = SymEquiv(s, _atom_site[l].fract_xyz)
h_pos = _atom_sites_Cartn_transform.matrix * h_pos
_geom_hbond.distance_HA = Norm ( h_pos - a_pos )
Category:
geom_hbond
