I don't have any trouble collecting the few-hundred nm radiation scattered by a very large object (143 000 km) and creating an image, i.e. I can see Jupiter with visible light.
If you consider dmin (the "resolution") derives from 2{theta}max,
then when 2{theta} is 180 degrees (is any higher angle data possible?),
theta is 90, so sin{theta} is 1,
and substituting into the Bragg equation will give dmin of 0.5 wavelength.
won't it?
Peter Moody
Henry Wellcome Laboratories of Structural Biology
Department of Biochemistry
Henry Wellcome Building
University of Leicester
LE1 9HN
0116 229 7097
________________________________
From: CCP4 bulletin board on behalf of Carlos Frazao
Sent: Wed 24/01/2007 09:09
To: [log in to unmask]
Subject: [ccp4bb] relation between wavelength and inter-atomic distances
Hi,
I have once heard and recently read that "the diffraction event results
from the fact that both the X-rays wavelength and the atomic distances
are of the same magnitude". Although such a relation seems appealing I
am unsure if this is not a mere coincidence. Could someone clarify or
lead me to a relevant reading.
Cheers,
Carlos
--
**************************************
Dr. Carlos Frazao
Crystallography Department
ITQB-UNL, Av Republica, Apartado 127
2781-901 Oeiras, Portugal
Phone: (351)-214469666
FAX: (351)-214433644
e-mail: [log in to unmask]
www.itqb.unl.pt
|