Polymers Subcommittee Agenda and Minutes
Tuesday, March 15, 2001
ICDD Headquarters, Conference Room A
Chairman: Sanjeeva Murthy
S. Murthy (Subcommittee Chairman) called the meeting to order at 8:00 a.m.
S. Murthy (Opening Remarks)
This is the first polymers subcommittee meeting. The purpose of this meeting is as follows:
Review what has been done in the last six months.
We had 9 examples in the example polymer database to show today.
How we should formulate the future polymer database.
What we want to accomplish in the future.
We would like to have volunteers to submit more examples for the polymer database.
Question: Any objections to the last minutes?
Answer (T. Blanton): No
Nobody else objected.
The board feels that we have enough to do to create a new polymer subcommittee.
We thanked J. Faber for his active work on this the last two years.
J. Faber has created a PDF3 type of an example database, which will be very useful for the diffraction users. Polymer database users are like clay database users. This demo database is very easy use.
J. Faber (showing his example polymer database)
Thanked T. Blanton, J. Kaduk, and S. Murthy as catalysts.
The purpose of this example database is to stimulate discussions, and brainstorming from the audience.
The example database is produced by using Microsoft Access.
There are nine patterns in the example database.
Displaying digitized traces is non-trivial. (Example: Microsoft Chart Control package can only plot 4000 point)
We need to install ActiveX control on user systems.
The examples have simple maximizing, export, import features and they will be enhanced in the future.
One example of overlaying graphics for two polymer samples was shown.
Other features for the future include full patterns comparison, CIF (one of the universal file transfer format), pattern analysis, and documentation/reducing-/characterization of data.
Atomic coordinates and refinement are other issues.
We want to store raw data from the instrument. We would like to have correction and smoothing features.
Scaling will be a good feature to have.
Polymer databases could be used in the same as IR database.
Storage and scalability will need several gigabytes of space.
No hands were shown for people who used methods other than constant 2-theta data collection.
When submitting data, the type of instrument should be specified.
As a past user, we are interested in orientation (vs. amorphous),
Heat treatment will affect the pattern.
3-D, crystallinity, and small angles (super structures) are important.
SIF, which requires less storage space than AIDS, is a good direction to go.
There are too many features to implement all at once. We should use 2q scans (2D in ICDD parlance) to start and implement other features later.
In John Faber's example, atom coordinates are in the CIF file.
It is a good idea to put all polymer structures in on place.
Use of atom coordinates and space groups to calculate 2Ds to be compared with experimental 2D. We can manipulate the display to match the experimental display. We can build radial distribution functions.
We have to consider high-angle issues especially with RDF.
We should consider what kind of information we want to see in the database.
What is the polymer? How was it made: powder or other form? Whether the data collected in transmission mode or other geometry. These are some of the information we need in the header.
Requirement for PDF-3 is a good starting point (example: step size).
T. Blanton is the GiA Chair and has GiA's lists of requirements, which can be used as a reference.
Notation for the sample name needs to be worked out.
We can use Common Name plus CAS number.
We can use existing data and their stick diagrams.
We can port PDF-2 polymers to this database
We want to take advantage of available data.
ACTIONS to take
We want to convince people to submit patterns.
We can digitize DOW Chemical Book (or others) - (J. Kaduk : It is not a bad idea.)
First requirements are 1D and 2D patterns.
T. Blanton will send Preliminary criteria lists to members to modify.
The example CD-ROMs will also be sent to members.
The meeting was adjourned at 9:00AM.