From 3d0dcb58cc0e04ad100dda5ca8a9e5da6c8334da Mon Sep 17 00:00:00 2001 From: "James.Hester" Date: Thu, 28 Sep 2023 12:17:30 +1000 Subject: [PATCH 1/2] Corrections from para (6) of document. --- cif_mag.dic | 49 ++++++++++++++++++++++++------------------------- 1 file changed, 24 insertions(+), 25 deletions(-) diff --git a/cif_mag.dic b/cif_mag.dic index d37e134..50cd7dc 100644 --- a/cif_mag.dic +++ b/cif_mag.dic @@ -2896,28 +2896,27 @@ save_space_group_magn.ssg_name _definition.update 2016-10-10 _description.text ; - The Belov-Neronova-Smirnova (BNS) symbol for a magnetic - superspace group (MSSG) is based on the symbol of the - non-magnetic superspace group (SSG) obtained by eliminating all - time-reversed operators from the group, as listed in the ISO(3+d)D - tables of Stokes and Campbell. If the magnetic basic space group - (MBSG) is of type-1 or type-3 (also known as type-3a), its BNS symbol - merely replaces that of the basic space-group (BSG). If the MBSG - is of type-2 or type-4 (also known as type-3b), an additional - phase-shift symbol associated with the time-reversal generator is added - to each modulation vector. If the MBSG is of type-4, the BNS - symbol of the MSSG is further modified to explicitly show the - time-reversal generator (1') at the end, and the anti-centering - subscript is moved from the lattice symbol to the 1' so as to - clearly indicate the fractional external-space translation of - this generator. - The examples are based on SSG 47.1.9.3 Pmmm(0,0,g)ss0 in (3+1)D. + The symbol for a magnetic superspace group (MSSG) is based on the UNI + symbol of the basic magnetic space group (BMSG), realized in the limit + that all modulation amplitudes go to zero, and on the ISO(3+D) symbol + of the corresponding non-magnetic superspace group (SSG). The + corresponding SSG symbol is obtained by removing the time-reversal from + each time-reversed operation of a type-1 or type-2 MSSG, or by eliminating + all time-reversed operations for a type-3 or type-4 MSSG. For a type-1 + or type-3 MSSG, the MSSG symbol is obtained from the SSG symbol by + simply replacing the symbol of the non-magnetic basic space group (BSG) + with the UNI symbol of the BMSG. For a type-2 or type-4 MSSG, one must + further communicate each of the modulation phase shifts associated + with the time-reversal generator of the magnetic point group (MPG). + The _space_group_magn.ssg_number tag should always be used as the + unique MSSG identifier rather than relying on the MSSG symbol alone. + The examples are based on SSG 47.1.9.3 Pmmm(0,0,g)ss0 in (3+1)D. Analogous tags: msCIF:_space_group.ssg_name - Ref: ISO-MAG tables of H.T. Stokes and B.J. Campbell at - http://iso.byu.edu. ISO(3+d)D tables of H.T. Stokes and B.J. - Campbell at http://iso.byu.edu. + Ref: ISO-MAG tables of H.T. Stokes and B.J. Campbell at http://iso.byu.edu. + ISO(3+d)D tables of H.T. Stokes and B.J. Campbell at http://iso.byu.edu. + H.T. Stokes and B.J. Campbell, Acta Cryst. A 78, 364-370 (2022). ; _name.category_id space_group_magn _name.object_id ssg_name @@ -2933,25 +2932,25 @@ save_space_group_magn.ssg_name ; type-1 MBSG Pmmm ; - Pmmm1'(0,0,g)ss00 + Pmmm.1'(0,0,g)ss00 ; - type-2 MBSG Pmmm1', with no basic-cell or + type-2 MBSG Pmmm.1', with no basic-cell or modulated moments allowed ; - Pmmm1'(0,0,g)ss0s + Pmmm.1'(0,0,g)ss0s ; - type-2 MBSG Pmmm1', with magnetic modulations + type-2 MBSG Pmmm.1', with magnetic modulations allowed, but not basic-cell moments ; Pm'm'm(0,0,g)ss0 ; type-3 MBSG Pm'm'm ; - Pmmm1'_a(0,0,g)ss00 + Pmmm.1'_a(0,0,g)ss00 ; type-4 MBSG P_ammm with purely external anti-centering ; - Pmmm1'_a(0,0,g)ss0s + Pmmm.1'_a(0,0,g)ss0s ; type-4 MBSG P_ammm with superspace anti-centering ; From b7a6564c73f0697a02120d5ba354b0419b533f2c Mon Sep 17 00:00:00 2001 From: James Hester Date: Thu, 28 Sep 2023 13:00:29 +1000 Subject: [PATCH 2/2] Fix update date --- cif_mag.dic | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/cif_mag.dic b/cif_mag.dic index 50cd7dc..07cea7d 100644 --- a/cif_mag.dic +++ b/cif_mag.dic @@ -2893,7 +2893,7 @@ save_ save_space_group_magn.ssg_name _definition.id '_space_group_magn.ssg_name' - _definition.update 2016-10-10 + _definition.update 2023-06-01 _description.text ; The symbol for a magnetic superspace group (MSSG) is based on the UNI