Subject:

**FCF Files and Fourier Synthesis for VESTA**
I've been playing with the FCF_VESTA macro to visualize fourier difference maps in VESTA, as my structure is too large to make sense of the maps using Topas alone. However, it seems that there is some issue where it always swaps the negative and positive differences.

To attempt to combat this I created a macro closer to an alternative usable format (compared to the LIST 3 format of h,k,l, Fobs, sigma(F), Fc(real), Fc(imag)) for VESTA:

h,k,l, Fobs, Fcalc, Fc(real), Fc(imag), sigma(F)

This is using the similar macro to Martin's FCF_VESTA, but with the end being:

"%12.4f" = Sqrt( I_no_scale_pks );

"%12.4f" = Sqrt( Iobs_no_scale_pks );

"%12.4f" = Sqrt( M Get(scale) ( A01^2 - 2 A01 B11 + B11^2 ) );

"%12.4f" = Sqrt( M Get(scale) ( B01^2 + 2 A11 B01 + A11^2 ) );

"%12.4f" = Sqrt( Iobs_no_scale_pks_err );

This seems to fix the problem such that the difference maps I'm exporting into VESTA match those that Topas is creating using the fourier_map macro. However, I'm not quite sure I'm doing this correctly - as I am uncertain of my assignments for Fobs and Fcalc - even though swapping them creates the same issue. Any help in this matter would be sincerely appreciated.

Thanks!

-Ben

To attempt to combat this I created a macro closer to an alternative usable format (compared to the LIST 3 format of h,k,l, Fobs, sigma(F), Fc(real), Fc(imag)) for VESTA:

h,k,l, Fobs, Fcalc, Fc(real), Fc(imag), sigma(F)

This is using the similar macro to Martin's FCF_VESTA, but with the end being:

"%12.4f" = Sqrt( I_no_scale_pks );

"%12.4f" = Sqrt( Iobs_no_scale_pks );

"%12.4f" = Sqrt( M Get(scale) ( A01^2 - 2 A01 B11 + B11^2 ) );

"%12.4f" = Sqrt( M Get(scale) ( B01^2 + 2 A11 B01 + A11^2 ) );

"%12.4f" = Sqrt( Iobs_no_scale_pks_err );

This seems to fix the problem such that the difference maps I'm exporting into VESTA match those that Topas is creating using the fourier_map macro. However, I'm not quite sure I'm doing this correctly - as I am uncertain of my assignments for Fobs and Fcalc - even though swapping them creates the same issue. Any help in this matter would be sincerely appreciated.

Thanks!

-Ben