Non-Ambient Diffraction Subcommittee Agenda and Minutes

ICDD Non-Ambient Diffraction Subcommittee
Wednesday, 16 March 2005
3:00 - 4:00 p.m.
ICDD Headquarters, Conference Room D
Chairman: Andrew Payzant

Minutes of the March 2005 ICDD Non-Ambient Diffraction Subcommittee Meeting

Meeting was called to order by Andrew Payzant, who thanked subcommittee members who had responded to an e-mail solicitation sent in December regarding issues to consider at this meeting.

The minutes of last meeting (March 2004) were read by Mike Bennett. John Faber moved to approve the minutes as read, seconded by Scott Misture. Motion carried.

ICDD Board of Directors’ Liaison Report given by Daniel Louer, who reported that last year’s motion (regarding correction of zero point errors in PDF datafiles) had been considered and rejected by the board. The explanation given was that applying a zero point error correction might mask other errors, though it was agreed that such a correction would likely nevertheless improve the data.

There was some discussion of how flags are incorporated in PDF-4. Only one of the subcommittee members in attendance (John Faber) actually had first-hand experience with non-ambient data in PDF-4. He reported that non-ambient Flags (T, P, B) are in PDF-4 (and also PDF-2, though vendor software may not utilize these flags).

Subcommittee mission statement – minor revisions were suggested. A revised mission statement was unanimously approved which now reads:

The Non-Ambient Diffraction Subcommittee of the International Centre for Diffraction Data is organized to facilitate the use of non-ambient diffraction data by the scientific community. It makes recommendations to the ICDD about how diffraction data obtained at non-ambient conditions should be represented in the PDF, and suggests specific research activities that could result in production of non-ambient new patterns for the PDF. It also maintains contact with various research and administrative groups throughout the world to exchange information about new developments in non-ambient diffraction techniques and results.

There followed some discussion of possible new activities at DXC and publications in Powder Diffraction relevant to the objectives of the subcommittee.

Two motions were made for consideration by the Board:

  1. “When AIDS is rewritten, consideration should be given to improved handling of systematic errors, for instance, zero point errors, in diffraction data.”
    Moved by Mike Bennett, seconded by John Faber, unanimously carried.
  2. “The non-ambient subcommittee recommends that the RBD indicate explicitly the sample conditions including low-temperature, high-temperature, high-pressure, or combinations thereof.”
    Moved by Andrew Payzant, seconded by Scott Misture, unanimously carried.

Motion to adjourn followed.