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--- alternative_space_group_settings [2017/02/10 12:28] – johnsoevans
+++ alternative_space_group_settings [2022/11/03 15:08] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
+====== Alternative Space Group Settings ======
+From the forum 10/2/2017:
+It’s quite easy to add a new setting.
+For F2/m then first find the primitive version in SGCOM5.CPP which is P2/m (space group number 10).
+P2/m has a file in the sg directory called P2OM.SG and part that file looks like:
+<code topas>
+xyzs
+{
+                x, y, z
+                -x, y, -z
+                x, -y, z
+                -x, -y, -z
+} 4
+</code>
+The computer adapted symbol for P2/m in sgcom5.cpp looks like:
+   MCI1A000P2B000 { p2/m = p12/m1 = 10 - p112/m - p2/m11 }
+To add a line for F2/m then simply use:
+   MCI1A000P2B000 { F2/m }
+This will produce a file called F2OM.SG and part of it looks like:
+<code topas>
+xyzs
+{
+                x, y, z
+                -x, y, -z
+                x, -y, z
+                -x, -y, -z
+                ' +(1/2, 1/2, 0) -------------------------
+                x+1/2, y+1/2, z
+                -x+1/2, y+1/2, -z
+                x+1/2, -y+1/2, z
+                -x+1/2, -y+1/2, -z
+                ' +(1/2, 0, 1/2) -------------------------
+                x+1/2, y, z+1/2
+                -x+1/2, y, -z+1/2
+                x+1/2, -y, z+1/2
+                -x+1/2, -y, -z+1/2
+                ' +(0, 1/2, 1/2) -------------------------
+                x, y+1/2, z+1/2
+                -x, y+1/2, -z+1/2
+                x, -y+1/2, z+1/2
+                -x, -y+1/2, -z+1/2
+} 16 </code>
+Note, I don’t know what space group number to put for F2/m so I put 230 and I put the line at the bottom of the file.
+It’s up to the user to ensure the correct crystal system (ie. correct lattice parameter constraints).