[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: [sdpd] Re: Crystal structure solution and neutron Time of flight data

Hi,

Can I just point out that sweeping generalisations about
time-of-flight data do no-one any favours.  The real issue
is the diffractometer, not the time-of-flight source.  There are plenty
of medium-resolution constant wavelength powder neutron diffractometers
around too.

The high-resolution powder diffractometer (HRPD) at the ISIS 
time-of-flight source has a resolution (delta_d / d) in backscattering 
of 5 x 10-4 which means that it it delivers extremely well-resolved
peaks
across a substantial d-spacing range.  It has been used in 
'countless' structure refinements and numerous structure determinations,
including ones based on direct methods and global optimisation methods.

Admittedly, it has only been in operation for the last 22 years, so
perhaps
some people have not yet heard of it, let alone used it.....

Cheers,

Kenneth



-----Original Message-----
From: sdpd...@yahoogroups.com [mailto:sdpd...@yahoogroups.com] On Behalf Of
Armel Le Bail
Sent: 23 August 2007 09:15
To: sdpd...@yahoogroups.com
Subject: [sdpd] Re: Crystal structure solution and neutron Time of
flight data

Hi,

Looking at ToF data, one sees a few isolated peaks at large d(A) values
and soon a massive peak overlapping for the smallest d(A). The
difficulty to solve the structure comes from this huge overlapping (if
any), not from the peak asymmetry in itself (though it may contribute to
enlarge the overlapping).

Armel


 
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/sdpd/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/sdpd/join
    (Yahoo! ID required)

<*> To change settings via email:
    mailto:sdpd-digest...@yahoogroups.com 
    mailto:sdpd-fullfeatured...@yahoogroups.com

<*> To unsubscribe from this group, send an email to:
    sdpd-unsubscribe...@yahoogroups.com

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/