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*To*:*Multiple recipients of list <coredmg@iucr.org>***Subject**:**Some additional data items for the REFINE category****From**:**Brian McMahon <bm@iucr.org>***Date*:*Wed, 9 May 2001 09:58:01 +0100 (BST)**Reply-To*:*coredmg@iucr.org*

Dear Colleagues I wish to circulate some proposals for additions to the core dictionary. I shall treat them in three separate mailings. This first block is a small number of additional data items that Gotzon found useful for his modulated structures dictionary, but which have wider application. These were posted some months ago, and I should have circulated them with the last round of Core discussions; I can only apologise to Gotzon that I clean forgot to do so. Please read and comment at an early opportunity; it is a useful sign of the vitality of the Core dictionary if we can add entries expeditiously whenever a well-defined need arises. Best regards Brian ############ ## REFINE ## ############ data_refine_ls_F_calc_accuracy _name '_refine_ls_F_calc_accuracy' _category refine _type numb _enumeration_range 0.0: _definition ; The estimated accuracy in electrons (for X-ray diffraction) reached during the evaluation of the structure factor given by _refine_ls_F_calc_formula following the method outlined in _refine_ls_F_calc_details. ; data_refine_ls_F_calc_details _name '_refine_ls_F_calc_details' _category refine _type char loop_ _example 'Gaussian integration using 16 points' ; Bessel functions expansion up to 5th-order. Bessel functions estimated accuracy: better than 0.001 ; _definition ; Details concerning the evaluation of the structure factor given by _refine_ls_F_calc_formula. ; data_refine_ls_F_calc_formula _name '_refine_ls_F_calc_formula' _category refine _type char _definition ; Analytical expression used to calculate the structure factor. ; data_refine_ls_restrained_wR_factor_all _name '_refine_ls_restrained_wR_factor_all' _category refine _type numb _enumeration_range 0.0: _definition ; The weighted residual factors for all reflections used in the refinement, including explicitly the restraints applied in the least-squares process. The reflections also satisfy the resolution limits established by _refine_ls_d_res_high and _refine_ls_d_res_low. sum|w[Y(obs)-Y(calc)]^2^|^1/2^ wR = ------------------------------ + sum|wY(obs)^2^| {sum~r~(w~r~|P(calc)-P(targ)|^2^)}^1/2^ + {--------------------------------} { sum~r~(w~r~P(targ)^2^) } Y(obs) = the observed amplitude specified by _refine_ls_structure_factor_coef, Y(calc) = the calculated amplitude specified by _refine_ls_structure_factor_coef, w = the least-squares weight, P(calc) = the calculated restraint values, P(targ) = the target restraint values, w~r~ = the restraint weight specified in _refine_ls_restraints_weighting_scheme sum is taken over the specified reflections sum~r~ is taken over the restraints ; data_refine_ls_restraints_weighting_scheme _name '_refine_ls_restraints_weighting_scheme' _category refine _type char _definition ; The weighting scheme applied to restraints in the least-squares process. ;

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