Hi James,
Derek Logan wrote:
- When Rontgen discovered a new kind of light, he called it
"x-rays". Now only the Germans call them Rontgen rays.
Thanks for a great essay! Since I have nothing of real value
contribute here, I won't pass over the opportunity to be a
"besserwisser" (as the Swedes
- When Rontgen discovered a new kind of light, he called it "x-
rays". Now only the Germans call them Rontgen rays.
Thanks for a great essay! Since I have nothing of real value
contribute here, I won't pass over the opportunity to be a
"besserwisser" (as the Swedes say, using a borrowed wor
The question was: which is F+ and which F-.
I think the answer is that the hkl are in a right-handed axis system and
-h-k-l are in a left-handed one. So it's the guy who first decides which
are a,b,and c. I think his name is denzo.
BS
On Fri, 27 Jun 2008, James Holton wrote:
Ahh. The h
Ahh. The history of science. I've always wondered how these naming
conventions get decided. Who is the authority on what gets named after
who? Historically, it seems to vary a lot.
- When Patterson published his incredibly useful map he called it the
"F-square synthesis". Does anyone NOT
Thanks very much for this interesting discussion.
We should have that more often.
Marius
> -BEGIN PGP SIGNED MESSAGE-
> Hash: SHA1
>
> Le 26 juin 08 à 18:49, Ethan Merritt a écrit :
>
>> On Thursday 26 June 2008 09:36:16 am Serge Cohen wrote:
>>> Please some one tells me if I'm wrong ...
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Le 26 juin 08 à 18:49, Ethan Merritt a écrit :
On Thursday 26 June 2008 09:36:16 am Serge Cohen wrote:
Please some one tells me if I'm wrong ... but I though that indeed
one
is NOT supposed to measure anomalous difference from reflections h
and
t; To: 'Hidong Kim'
> Cc: CCP4BB@JISCMAIL.AC.UK
> Subject: RE: [ccp4bb] Friedel vs Bijvoet
>
> I quote from these pages:
>
> "Bijvoet pairs are Bragg reflections which are true symmetry
> equivalents to a Friedel pair. These true symmetry equivalents have
On Thursday 26 June 2008 11:35:31 am Bernhard Rupp wrote:
> Let's try this again, with definitions, and pls scream if I am wrong:
>
> a) Any reflection pair hR = h forms a symmetry related pair.
???
Maybe you meanh' = hR
>R is any one of G point group operators of the SG.
L PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Bernhard Rupp
> Sent: 26 June 2008 19:54
> To: 'Hidong Kim'
> Cc: CCP4BB@JISCMAIL.AC.UK
> Subject: RE: [ccp4bb] Friedel vs Bijvoet
>
> I quote from these pages:
>
> "Bijvoet pairs are Bragg refle
Bernhard Rupp wrote:
I quote from these pages:
"Bijvoet pairs are Bragg reflections which are true symmetry
equivalents to a Friedel pair. These true symmetry equivalents
have *equal amplitudes, even in the presence of anomalous scattering*."
This is poorly worded. I would change it to
There was a mistake in the letter that listed the Bijvoet pairs
for a monoclinic space group and that is confusing you. Let me
try.
The equivalent positions for a B setting monoclinic are
h,k,l; -h,k,-l.
The Friedel mates for the general position (h,k,l) are (-h,-k,-l).
This means tha
I quote from these pages:
"Bijvoet pairs are Bragg reflections which are true symmetry
equivalents to a Friedel pair. These true symmetry equivalents
have *equal amplitudes, even in the presence of anomalous scattering*."
Sounds more like centric or perhaps simply symmetry related to me.
A few
,
Hidong
Bernhard Rupp <[EMAIL PROTECTED]>
Sent by: CCP4 bulletin board
06/26/2008 11:35 AM
Please respond to
[EMAIL PROTECTED]
To
CCP4BB@JISCMAIL.AC.UK
cc
Subject
Re: [ccp4bb] Friedel vs Bijvoet
Let's try this again, with definitions, and pls scream if I am wro
Let's try this again, with definitions, and pls scream if I am wrong:
a) Any reflection pair hR = h forms a symmetry related pair.
R is any one of G point group operators of the SG.
This is a set of reflections (S). Their amplitudes
are invariably the same. They do not even show up
as
On Thursday 26 June 2008 09:36:16 am Serge Cohen wrote:
> Please some one tells me if I'm wrong ... but I though that indeed one
> is NOT supposed to measure anomalous difference from reflections h and
> h' if those are related by one of the symmetry operator of the point
> group...
This statement
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Please some one tells me if I'm wrong ... but I though that indeed one
is NOT supposed to measure anomalous difference from reflections h and
h' if those are related by one of the symmetry operator of the point
group...
That is in monoclinic (
I've always thought that a Bijvoet pair is any pair for which an
anomalous difference could be observed. This includes Friedel pairs
(h & h-bar), but it also includes pairs of the form h & h', where h'
is symmetry-related to h-bar. Thus Friedel pairs are a subset of all
possible Bijvoet pai
Friedel pair is strictly F(hkl) and F(-h,-k,-l).
Bijvoet pair is F(h) and any mate that is symmetry-related to F(-h), e.g.,
F(hkl) and F(-h,k,-l) in monoclinic.
There are always anomalous differences, though they can be unmeasurably
small.
Bernie Santarsiero
On Thu, June 26, 2008 10:55 am, Bernh
Dear All,
I wonder about the conventions using Friedel vs Bijvoet pair.
a) there are no differences. As long as h = -h, it's a Friedel
or a Bijvoet pair. They are the same.
b) A Friedel pair is any reflection h = -h including hR = -h, i.e.
including centric reflections.
A Bijvoet pair
19 matches
Mail list logo