mariahovhannesian
Hello all,
I am trying to refine some of the atoms anisotropically by addidng "adps ADPs_Keep_PD " at the end of the site line. However, sometimes I am getting non-positive definite values. As far as I understood ADPs_Keep_PD macro should keep them positive definite. I know the refinement of these anisotropic parameters to non-positive definite values might indicate a greater problem but now I am only trying to understand why ADPs_Keep_PD macro is not functioning as I expected. Thanks for your answer.
alancoelho
I just looked and the macro seems to be in error; ie.
move_to u11 min 0
move_to u22 min 0
move_to u33 min 0
move_to u12 min = -Sqrt(Get(u11) Get(u22)); max = Sqrt(Get(u11) Get(u22));
move_to u13 min = -Sqrt(Get(u11) Get(u33)); max = Sqrt(Get(u11) Get(u33));
move_to u23 min = -Sqrt(Get(u22) Get(u33)); max = Sqrt(Get(u22) Get(u33));
It should be:
move_to u11 min 0
move_to u22 min 0
move_to u33 min 0
move_to u12 min 0 max = Sqrt(Get(u11) Get(u22));
move_to u13 min 0 max = Sqrt(Get(u11) Get(u33));
move_to u23 min 0 max = Sqrt(Get(u22) Get(u33));
Please make the change and see what happens.
cheers
alan