Quoting Alan Hewat <[EMAIL PROTECTED]>: > > There were discussions about the factors that may cause negative atomic > > displacement parameters for XRD data. What about neuton data and how to > > solve the problem (time-of-flight data in this case) ? > > Negative temperature factors Biso mean that low d-spacing (high-Q :-)) > peaks are stronger than they should be.
One way to obtain negative thermal factors is to use a poor background function for severely overlapped data going to very short d-spacings (high-Q). The peaks look stronger when you put the background is too low. Needs a lot of overlap before you can manage to do it. HTH, Jon ------------------------------------------------- This mail sent through IMP: http://horde.org/imp/
