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James.
(message from core DMG chair follows)
�Dear Colleagues,
Last September I circulated for fast track approval a recommendation for adding a new item:����������������������������
���������������� _diffrn_radiation_wavelength_nominal,
to the core dictionary (see below for details).� The intent was that this could be used for giving a nominal wavelength calculated e.g., from the parameters of a diffractometer.� It was proposed that this might be needed for completeness even though it was not accurate enough for calculating� lattice parameters, etc.� This proposal was passed by the core CIF dictionary maintenance group by default (no one raised any objection).� When this proposal was subsequently presented for final approval to COMCIFS, Nick Spadaccini suggested a more elegant alternative, namely that by adding instead the item
������� _diffrn_radiation_wavelength_determination
we could loop the nomiinal wavelength with the� refined (and any other interesting) wavelengths.� This would be more informative and allow for future expansion.
An example of how this might be used is:
�������� loop_
������������ _diffrn_radiation_wavelength_id
������������ _diffrn_radiation_wavelength
������������ _diffrn_radiation_wavelength_determinaton
��������������� 1�� 1.23456�� fundamental
��������������� 2�� 1.25����� estimated
According to our rules, this proposal was posted for comment to the coreCIF dictionary maintenance group for six weeks.� Two comments were received, neither raising any serious objection
David Brown
Chair Core CIF Dictionary Maintenance Group
COMMENTS FROM CORE CIF DICTIONARY MANAGEMENT GROUP
--------------------------------------------------
Comment from Jim Kaduk
I think this enumerated data item gets us to where we want to be.� We�
want to document the wavelength(s) used in the experiment, as well as�
how it was determined.� Knowing both, one could change/correct the�
wavelength later if desired for some particular purpose.
Comment from R. Curtis Haltiwanger
Research Scientist
Cephalon, Inc.
610-738-6853
As I said I have only used lab sources, so I have not needed other wavelengths.
That makes it hard for me to comment on this further extension.�
In general, I like including additional information.�
Probably because of my lack of experiance this extension seems complicated to me.
I'll leave it to others to comment and evaluate.
PROPOSED DICTIONARY CODE
------------------------
Add new item to DDL1 Core CIF dictionary
data_diffrn_radiation_wavelength_determination
� _name��������������������� '_diffrn_radiation_wavelength_determination'
� _category������������������� diffrn_radiation_wavelength
� _type����������������������� char
� _list����������������������� both
� _list_reference����������� '_diffrn_radiation_wavelength_id'
�loop_
�� _enumeration
�� _enumeration_detail
���� 'fundamental'����������
�'Wavelength that is a fundamental property of matter e.g. MoK\alpha'
���� 'estimated'��������������
�'Estimated from secondary information e.g. monochromator angle or time of flight'
���� 'refined'����������������
�'Based on refinement using a standard material with known cell parameters'
� _definition
;������������� The method of determination of incident wavelength. Further information may be provided in _diffrn_radiation_special_details
;
Reply to: [list | sender only]
Revised fast-track proposal on wavelength passes DMG review
- To: "Discussion list of the IUCr Committee for the Maintenance of the CIFStandard (COMCIFS)" <[email protected]>
- Subject: Revised fast-track proposal on wavelength passes DMG review
- From: James Hester <[email protected]>
- Date: Tue, 12 Jan 2010 12:15:53 +1100
James.
(message from core DMG chair follows)
�Dear Colleagues,
Last September I circulated for fast track approval a recommendation for adding a new item:����������������������������
���������������� _diffrn_radiation_wavelength_nominal,
to the core dictionary (see below for details).� The intent was that this could be used for giving a nominal wavelength calculated e.g., from the parameters of a diffractometer.� It was proposed that this might be needed for completeness even though it was not accurate enough for calculating� lattice parameters, etc.� This proposal was passed by the core CIF dictionary maintenance group by default (no one raised any objection).� When this proposal was subsequently presented for final approval to COMCIFS, Nick Spadaccini suggested a more elegant alternative, namely that by adding instead the item
������� _diffrn_radiation_wavelength_determination
we could loop the nomiinal wavelength with the� refined (and any other interesting) wavelengths.� This would be more informative and allow for future expansion.
An example of how this might be used is:
�������� loop_
������������ _diffrn_radiation_wavelength_id
������������ _diffrn_radiation_wavelength
������������ _diffrn_radiation_wavelength_determinaton
��������������� 1�� 1.23456�� fundamental
��������������� 2�� 1.25����� estimated
According to our rules, this proposal was posted for comment to the coreCIF dictionary maintenance group for six weeks.� Two comments were received, neither raising any serious objection
David Brown
Chair Core CIF Dictionary Maintenance Group
COMMENTS FROM CORE CIF DICTIONARY MANAGEMENT GROUP
--------------------------------------------------
Comment from Jim Kaduk
I think this enumerated data item gets us to where we want to be.� We�
want to document the wavelength(s) used in the experiment, as well as�
how it was determined.� Knowing both, one could change/correct the�
wavelength later if desired for some particular purpose.
Comment from R. Curtis Haltiwanger
Research Scientist
Cephalon, Inc.
610-738-6853
As I said I have only used lab sources, so I have not needed other wavelengths.
That makes it hard for me to comment on this further extension.�
In general, I like including additional information.�
Probably because of my lack of experiance this extension seems complicated to me.
I'll leave it to others to comment and evaluate.
PROPOSED DICTIONARY CODE
------------------------
Add new item to DDL1 Core CIF dictionary
data_diffrn_radiation_wavelength_determination
� _name��������������������� '_diffrn_radiation_wavelength_determination'
� _category������������������� diffrn_radiation_wavelength
� _type����������������������� char
� _list����������������������� both
� _list_reference����������� '_diffrn_radiation_wavelength_id'
�loop_
�� _enumeration
�� _enumeration_detail
���� 'fundamental'����������
�'Wavelength that is a fundamental property of matter e.g. MoK\alpha'
���� 'estimated'��������������
�'Estimated from secondary information e.g. monochromator angle or time of flight'
���� 'refined'����������������
�'Based on refinement using a standard material with known cell parameters'
� _definition
;������������� The method of determination of incident wavelength. Further information may be provided in _diffrn_radiation_special_details
;
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