PROC-NAME: CELLV02 Type_1

PURPOSE: To check that the _cell_volume su matches _cell_length_ and _cell_angle_ su values.

PROCEDURE: (Ref: Giacovazzo Fundamentals of Crystallography p.122)

CALCULATE

CSA = COSINE[_cell_angle_alpha]

CSB = COSINE[_cell_angle_beta]

CSG = COSINE[_cell_angle_gamma]

SA = SINE[_cell_angle_alpha]

SB = SINE[_cell_angle_beta]

SG = SINE[_cell_angle_gamma]

A1 = (su of a)/_cell_length_a

A2 = (su of b)/_cell_length_b

A3 = (su of c)/_cell_length_c

B1 = SA*(CSA-CSB*CSG)*(su of alpha)

B2 = SB*(CSB-CSA*CSG)*(su of beta)

B3 = SG*(CSG-CSA*CSB)*(su of gamma)

CV = [(_cell_length_a*_cell_length_b*_cell_length_c)**4/(_cell_volume)**2]

SUVOL = SQRT{(_cell_volume)**2*(A1**2+A2**2+A3**2)+CV*(B1**2+B2**2+B3**2)}

DSUV = |{su of cell volume}-SUVOL|

TEST

IF DSUV > 8 issue ALERT A

? ? ? ? "Alert A The supplied cell volume s.u. differs from that calculated from the cell parameter s.u.'s by > 8"

DSUV > 4 issue ALERT B

? ? ? ? "Alert B The supplied cell volume s.u. differs from that calculated from the cell parameter s.u.'s by > 4"

DSUV > 2 issue ALERT C

? ? ? ? "Alert C The supplied cell volume s.u. differs from that calculated from the cell parameter s.u.'s by > 2"

? ? ? ? There is a discrepancy between the standard uncertainty (s.u.) for the unit cell volume given in the CIF and that calculated from the s.u.s of the unit cell dimensions given in the CIF. Check the volume and cell dimension s.u.s for typographical errors (rule of '19' applies).

(http://journals.iucr.org/services/cif/checking/CELLV_02.html)

目的：檢查單胞體積(_cell_volume)標(biāo)準(zhǔn)不確定度(s.u., standard uncertainty)與單胞長度(_cell_length_)和單胞角度(_cell_angle_)的標(biāo)準(zhǔn)不確定度是否相符。

若DSUV大于8，發(fā)布A類警告

? ? ? ? "Alert A The supplied cell volume s.u. differs from that calculated from the cell parameter s.u.'s by > 8"

若DSUV大于4，發(fā)布B類警告

? ? ? ? "Alert B The supplied cell volume s.u. differs from that calculated from the cell parameter s.u.'s by > 4"

若DSUV大于2，發(fā)布C類警告

? ? ? ? "Alert C The supplied cell volume s.u. differs from that calculated from the cell parameter s.u.'s by > 2"

? ? ? ? CIF中單胞體積的標(biāo)準(zhǔn)不確定度和通過單胞尺寸的標(biāo)準(zhǔn)不確定度計算得到的數(shù)值不相符。檢查單胞體積和單胞尺寸的標(biāo)準(zhǔn)不確定度是否存在排版錯誤。

解決策略：一般不會出現(xiàn)這種情況，檢查是否晶胞參數(shù)輸入錯誤。