Yes, I think it might be saying the same thing: resolution is a function of the distance from the origin in reciprocal space.
I was surprised that a reflection with all-higher Miller indices would be equivalent resolution--but I suppose I was stuck in my orthogonal-axis world.
JPK
-----Original Message-----
From: Tim Gruene [mailto:[log in to unmask]]
Sent: Friday, April 15, 2016 12:30 PM
To: Keller, Jacob
Cc: [log in to unmask]
Subject: Re: [ccp4bb] Detwinning Centric Reflections?
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Dear Jakob,
the inverse resolution of a reflection equals the length of the vector h*astar + k*bstar + l*cstar.
does this explain your 'PS'?
Best,
Tim
On Friday, April 15, 2016 04:08:56 PM Keller, Jacob wrote:
> Dear Crystallographers,
>
> In detwinning a dataset, I noticed that correction of the intensity
> distributions works dramatically better for the acentric versus
> centric (see attached plots). In this case it is P3212 and the twin
> operator is (-h,-k,l). Can anyone suggest why this might be the case?
> Should the algorithm be different for centrics than for acentrics (I
> can't see why...)?
>
> All the best,
>
> Jacob Keller
>
> PS: btw, I came across an interesting phenomenon in this spacegroup
> which experienced crystallographers no doubt will be aware of, but
> just felt it amusing enough to share. When there is a non-orthogonal
> axis, HKL's of seemingly-different resolution can be the same
> resolution. For example, in this spacegroup, the two reflections
> (3,2,4) and (-5,3,4) are equivalent reflections and are of the exact
> same resolution. This is because when one "walks down" the H axis in
> reciprocal space 3 units and up 2 units in K, the walk up K takes you
> *farther* from the origin due to the 60 deg angle between K and H.
> Conversely, when one walks down H -5 units, then up 3 units, the 3
> units in K bring you *closer* to the origin, again due to the tilt of
> K with respect to H. I thought this might be interesting to somebody out there.
>
>
> *******************************************
> Jacob Pearson Keller, PhD
> Looger Lab/HHMI Janelia Research Campus
> 19700 Helix Dr, Ashburn, VA 20147
> email: [log in to unmask]
> *******************************************
- --
- --
Paul Scherrer Institut
Tim Gruene
- - persoenlich -
OFLC/102
CH-5232 Villigen PSI
phone: +41 (0)56 310 5297
GPG Key ID = A46BEE1A
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