Bernhard
Refmac doesn't specify a target value for the chiral volume, it just
specifies 'positive' or 'negative'. It presumably uses the chiral
volume computed from the input co-ords as the target, so this is updated
as the refinement proceeds. I guess the goal isn't to restrain the
geometry to
Bernhard and Ian,
Since you ask, SHELXL defines a chiral volume as the volume of the
'unit-cell' that can be constructed using the three interatomic
vectors from the atom in question. I think that I took this from
PROLSQ, and that Bernhard's formula (which corresponds to the
value of a
: Bernhard Rupp b...@ruppweb.org
To: CCP4BB@JISCMAIL.AC.UK
Sent: Friday, April 3, 2009 9:21:03 PM
Subject: [ccp4bb] chiral volume target value
Dear All,
assuming the chiral volume definition with r() a Cartesian position vector
Vc = [r(N)-r(Ca)]*([r(C)-r(Ca)]x[r(Cb)-r(Ca)])
I always get about -0.65
it is
defined by
this parameter:
chir_volume_esd = 0.2
I believe this is the same value as used in refmac.
Ralf
- Original Message
From: Bernhard Rupp b...@ruppweb.org
To: CCP4BB@JISCMAIL.AC.UK
Sent: Friday, April 3, 2009 9:21:03 PM
Subject: [ccp4bb] chiral volume target value
Dear All
Dear All,
assuming the chiral volume definition with r() a Cartesian position vector
Vc = [r(N)-r(Ca)]*([r(C)-r(Ca)]x[r(Cb)-r(Ca)])
I always get about -0.65 A**3
Is this correct? Are there any target values?
In a SHELX manual I read + 2.5 for the chiral volume - seems to
be different.
(not
