Harold T. Stokes. Branton J. Campbell, and Dorian M. Hatch
Department of Physics and Astronomy, Brigham
Young University, Provo, Utah
Version 3.1.2, Oct 2023.
(1) Replaced incorrrect_atom_site_Wyckoff_label tag with correct _atom_site_Wyckoff_symbol tag in all CIF output.
(2) Updated tag _space_group_magn.point_group_name to _space_group_magn.point_group_name_UNI in incommensurate magnetic CIF output.
(3) Updated tag _space_group_magn.point_group_number tag to _space_group_magn.point_group_number_Litvin tag in magnetic CIF output.
(4) In CIF output, justified the numeric columns belonging to atomic coordinates, magnetic moments, and rotational moments on the decimal point and added space between columns so that negative numbers don't ruin the justification.
Version 3.1.1, Aug 2023. Fixed some minor bugs.
Version 3.1.0, Jan 2022. Implemented UNI (unified) symbols for
magnetic space groups and superspace groups.
Version 3.0.3, Sep 2021. Now reads magnetic moments which are
represented in spherical (xcart||a, zcart||c*) rather than
crystal-axis components, meaning that the item on the
_atom_site_moment.* category is spherical_modulus,
spherical_azimuthal, and spherical_polar rather than crystalaxis_x,
crystalaxis_y, and crystalaxis_z. If the moments are provided in both
coordinate systems, only the crystal-axis coordinates will be read.
Version 3.0.2, Jun 2021. Changed the way that incommensurate k
vectors are represented internally; this extensive revision should be
invisible to users.
Version 3.0.1, Jan 2021. The read-CIF subroutine now accepts
both "+1" or "1" for the magnetic component of a symmetry operation.
Version 3.0.0, Jul 2020.
(1) The CIF creation form now enables the input of incommensurate structures.
(2) All recent enhancements in the FINDSYM symmetry-detection routines were propagated to the symmetry-detection feature in ISOCIF, which has been renamed as "Detect higher symmetry". This includes the detection of superspace-group and magnetic superspace-group symmetry in modulated structures.
(3) A "Remove incommensurate modulations" feature was added, which results in the commensurate structure obtained in the limit that all modulation amplitudes go to zero. If the atomic parameters of the basic unit cell are not sufficiently general in this symmetry group, the subsequent application of the "Detect higher symmetry" routine may increase the symmetry.
(4) The "Remove magnetic moments" feature was extended to incommensurate magnetic structures, and results in the non-magnetic superspace-group symmetry realized in the limit that all magnetic modulation amplitudes go to zero.
(5) The "Reduce to P1 symmetry" feature was extended to accomodate incommensurate structures, and results in a superspace-group or magnetic superspace group of appropriate internal dimension with only the identity element in its point group.
(6) The "Save CIF file" feature was extended to accomodate arbitrary setting transformations of an incommensurate structure, provided that the resulting symmetry elements do not contain rational fractions in the point components or incommensurate/decimal terms in the translational components.
(7) Together, the "Detect higher symmetry", "Remove magnetic moments", "Reduce to P1 symmetry", "Remove incommensurate modulations", and CIF alternative-setting features produce a powerful suite of capabilities for manipulating both incommensurate and commensurate structures.
(8) The user is now warned when attempting to apply an incommmensurate/decimal origin shift that would result in incommensurate/decimal fractions in the symmetry operators of either commensurate or incommensurate structures.
(9) The allowed length of an atom-type symbol was uniformly extended from 2 to 6 characters in all subroutines.
(10) Other bug fixes and enhancements.
Version 2.7.0, Nov 2019. (1) cell volume added to CIF output; (2) significantly improved ability to function with large displacive tolerances; (3) In parallel with changes to ISODISTORT, the jnlp delivery of interactive visualizations has been replaced by the stand-alone ISOVIZ application; one must now save an ascii-data file and then open it in ISOVIZ to visualize a structure; (4) preparation for future CIF-output features.
Version 2.6.0, Apr 2018. ISOCIF now fully supports the atomic rotation vectors generated by ISODISTORT, which are very nicely analogous to magnetic-moment vectors. For a rigid-unit rotation, one can indicated the magnitude and direction of the rotation by assigning a pseudo-vector to the pivot atom (possibly a dummy atom) at the center of the rigid unit. This can be done to match the actual rigid-unit rotation realized in the structure or to indicate a possible but unrealized rotation. ISOCIF does not attempt to actually move the passenger atoms of a rigid-unit to match the pivot-atom rotation vector. The pivot-atom rotation vectors of a structure can represent a pattern of rigid-unit rotations even when no passenger atoms are explicitly given in the CIF.
Version 2.5.1, Nov 2017. Minor bug fixes.
Version 2.5.0, Aug 2017. Recent improvements to FINDSYM have propgated to ISOCIF. (1) Fundamental symmetry-detection algorithm and efficiency improvements, particularly for cases involving large numbers of atoms and for cases involving substantial "noise" in the atomic coordinates. (2) Errors encountered at large tolerance values have been resolved. When a large tolerance is requested, that tolerance is now reset to 1/3 the smallest same-atom-type nearest-neighbor distance for each atom type.
Version 2.4.1, Jan 2017. Minor bug fixes.
Version 2.4.0, Nov 2016. (1) Now accepts uppercase X,Y,Z symbols in space-group operators from CIF input. (2) Recent improvements to FINDSYM's symmetry-detection routines carry over to ISOCIF. (3) Implemented several user-adjustable tolerances under the "find actual symmetry tab". (4) Because the magCIF format has now been approved by the IUCr, all magnetic CIF read/write routines have been updated to the new standard but can still read magnetic CIF files that use the slightly-different interim standard. The old (pre-May2014) magnetic CIF prototype can no longer be used. (5) Minor bug fixes.
2.3.13, Aug 2016. Preparations for new features.
2.3.12, Oct 2015. Fixed a variety of bugs related to symmetry detection, magnetic symmetry, non-standard settings in CIF output, the ability and efficiency to deal with larger structures, and some minor cosmetic issues.
2.3.8-11, Aug 2014. Various minor bug fixes.
2.3.7, Jun 2014. (1) This version uses the provisional magCIF
format for describing commensurate magnetic structures. Commensurate
parent and child structures can be imported using either the
provisional magCIF format or our older magnetic-CIF format, though the
older format will eventually be abandoned. At present, one can use
ISOCIF to convert from the old to the new format.
(2) Improved capabilities for dealing with structures with large
numbers of atoms.
(3) The ability to read magnetic CIFs in non-standard BNS settings.
Upon upload, the structure is transformed to a standard setting, and
the transformation matrix is provided to the user.
(4) CIF input must now be uploaded -- the cut/paste options has been
eliminated. The separate pre-processed CIF page for
reviewng/accepting uploaded CIF content has also been eliminated.
(5) Many incremental developments and bug fixes accumulated during the
past year.
2.3.6, May 2013, Introduced new nonstandard tags in CIF files
to give information about space-group settings.
2.3.5, Mar 2013. Fixed bugs that caused the program to crash
sometimes.
2.3.4, 22 Jan 2013. Fixed bug. Spurious output produced in CIF file
output.
2.3:
(1) Displays transformation to current space-group setting
(a) when uploaded CIF file is in a non-standard setting and (b) when
the "Find actual symmetry" option is selected.
(2) Added the capability to create CIF files using nonstandard settings.
2.2:
Capability to remove magnetic moments.
2.1:
Capability to reduce symmetry to P1.
2.0:
Magnetic moments and magnetic space groups.
1.3:
Option to change lattice vectors and origin of space group.