Powder dictionary (pdCIF) version 1.0.1
Category PD_DATA
Name:'_pd_data_[pd]'
Definition:
The PD_DATA category contains raw, processed and calculated data points in a diffraction data set. In many cases, it is convenient to tabulate calculated values against the raw and processed measurements, and so the various _pd_meas_, _pd_proc_ and _pd_calc_ data items belonging to this category may be looped together. In some instances, however, it makes more sense to maintain separate tables of the data contributing to the measured and processed diffractograms (for example, a profile may be calculated at 2theta values different from those of the measured data points). To facilitate the identification of equivalent points in these separate tables, separate identifiers are defined.Examples:
Example 1 - data set collected for a two-phase sample (Al~2~O~3~/Si)
by B. H. Toby, '1997-01-29T16:37|POWSET_01|B.Toby|..NIST-D5000'.
loop_
_pd_data_point_id
_pd_meas_intensity_total
_pd_proc_ls_weight
_pd_proc_intensity_bkg_calc
_pd_calc_intensity_total
1 240(15) 0.00417 214.5 214.5
2 219(15) 0.00457 214.3 214.2
3 206(14) 0.00485 214.0 214.0
4 212(15) 0.00472 213.8 213.7
5 190(14) 0.00526 213.5 213.5
6 203(14) 0.00493 213.2 213.2
# - - - - data truncated for brevity - - - -
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Example 2 - the data of Example 1 split into three separate tables.
loop_
_pd_meas_point_id
_pd_meas_intensity_total
1 240(15) 2 219(15) 3 206(14) 4 212(15) 5 190(14) 6 203(14)
loop_
_pd_proc_point_id
_pd_proc_ls_weight
_pd_proc_intensity_bkg_calc
1 0.00417 214.5 2 0.00457 214.3
3 0.00485 214.0 4 0.00472 213.8
5 0.00526 213.5 6 0.00493 213.2
loop_
_pd_calc_point_id
_pd_calc_intensity_total
1 214.5 2 214.2 3 214.0 4 213.7 5 213.5 6 213.2
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Example 3 - hypothetical example where the measured and calculated
points are not in one-to-one correspondence.
loop_
_pd_meas_point_id
_pd_meas_2theta_scan
_pd_meas_intensity_total
1 21.0 24
2 21.2 32
3 21.4 67
4 21.6 98
loop_
_pd_calc_point_id
_pd_proc_2theta_corrected
_pd_calc_intensity_total
1 21.0 26
1a 21.3 56
4 21.6 76
4a 21.9 90
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Type: null
Category: category_overview
