The first line:
The title, which does not affect
the phasing process.
STATUS(by
default = 0)
0: for unknown
structures
1: for known
structures, comparison will be made between the given and DIMS-derived
phases of the satellites
PATH(=3)
1: for phasing
the satellites of incommensurate structures with known phases of the mains,
and the WEAK-WEAK relationships are used such that the obtained phases
of the nth-order satellites are taken as known phases for phasing the (n+1)th-order
satellites. Only one of the 1st-order satllites is assigned a 'known'
phase ZP1 to determine the origin of the 4th axis.
2: for phasing
the satellites of incommensurate structures with known phases of the mains,
and the WEAK-WEAK relationships are neglected for phasing all the satellites.
One of each nth-order satllites is assigned a 'known' phase in phasing
procedure. In this case, you can assign these 'known' phases ZPn.
3: for phasing
the satellites of incommensurate structures with known phases of the mains,
the satellites with order greater than 1 are phased using PATH=2 and then
WEAK-WEAK relationships are used to determine the ORIGIN-DEPENDING PHASE
SHIFT.
4: phasing
for composite structures, the WEAK-WEAK relationships are neglected.
ZPn
phase value
of an nth-order satellite, which is used as the origin-fixing reflection
for phasing the nth-order satellites.
ORDER(=2)
0: phasing
for mains with phases of certain number of mains being known.
>0: for PATH
equal 1 ,2 or 3, up to ORDERth-order satellites will be phased with known
phases of all the mains.
128: for PATH
equal 4, only mains will be phased.
129: for PATH
equal 4, all satellites will be phased with known phases of all the mains,
and the WEAK-WEAK relationships are neglected.
130: for PATH
equal 4, all mains and satellites can be phased together with WEAK-WEAK
relationships neglected (not recommended).
RANTP
(=0) active only for acentric space group with PATH=4
0: random
phases of 45/135/225/315 are assigned
1: random
phases of 0/180 are assigned
RADIUS
(=0)
0: input
phases in degree.
1: input
phases in radius.
MAXREL
maximum number
of sigma2 relations acceptable for a single reflection.
KPMAX
(=50.0)
sigma2-relationships
with kapa greater than KPMAX are to be eleminated.
KPMIN
(=0.0)
a parameter
(ranging from 0.0 to 2.0) for eleminating sigma2-relationships with kapa
less then KPMIN.
PPERC
(=1.0)
the strongest
PPERC ´ 100 % reflections will be phased,
active only when phasing main reflections of composite structures (PATH=4,
ORDER=128).
NTRIAL
(=50)
number of
trials, i.e. the number of random-starting phase sets (max. NTRIAL = 1024).
SKIP
(=0)
skip the first
SKIP trials.
NFSn
(n = 0, 1, ..., 6)
> or = 0:
output the phase set containing up to the nth-order satllites selected
by CFOM.
< 0: abs(NFSn)
will be the serial number of the set that you want to output disregarding
the value of CFOM.
CLCTR
(=0.005)
a parameter
to control dynamically the number of cycles of phase refinement.
MAXCL
(=10)
max number
of cycles for tangent-formula iteration.
NCLFIX
(=6)
in the first
NCLFIX cycles for tangent-formula iteration the KNOWN phases are kept FIXED,
after that they are changeable during the refinement.
A1, B1,
C1, ALFA1, BETA1, GAMA1
unit-cell
parameters of the BASIC STRUCTURE for modulated structures, or of the FIRST
SUB-STRUCTURE for composite structures.
A2, B2,
C2, ALFA2, BETA2, GAMA2
unit-cell
parameters of the SECOND SUB-STRUCTURE for composite structures.
K1,
K2,
K3
the a*, b*
and c* components of the modulation wave vector q, i.e.
q
= k1a* + k2 b*
+ k3 c*
W1
(=0.2), W2 (=1.4), W3
(=1.4)
weights of
the figures of merit ABSFOM, PSI-ZERO and RISIDUAL in the calculation of
the combined figure of merit CFOM
NOIN
in the cell
contents, the top NOIN elements belong to the first sub-structure of the
composite structures, active only when phasing main reflections of composite
structures i.e. when PATH=4 and ORDER=128.
NORMAL
0/1 corresponds
one of the two strategies for scaling Fobs, active only when PATH=4
and ORDER=128.
STATIS
0: no WILSON
statistics will be performed
1: WILSON
method is used to scale Fobs
2: K-curve
method is used to scale Fobs, active only when PATH=4
and ORDER=128.
BFACTOR
0.0: the B-factor
from WILSON statistics is used for scaling, else: BFACTOR is used instead
of the B-factor from WILSON statistics; active only when PATH=4,
ORDER=128
and STATIS=1.
NWLSTEP
(=16)
number of zones
to be divided in reciprocal space for WILSON statistics
ELEMENT
chemical symbol
of atoms in the cell
ATOMIC
NR
atomic number
of the specified chemical element
NUMBER
number of
atoms in the cell
SUPERSPACE
GROUP: TWO-LINE SYMBOL or NGENE
Here you can
just give the two-line symbol, such as
P[C 2/M]-1 S :B
for the sample data of g -Na2CO3.
For more details, please refer to Fu Zheng-qing & Fan Hai-fu (1997)
"A computer program to derive (3+1)-dimensional symmetry operations from
two-line symbols" J. Appl. Cryst. 30, 73-78. Or, if you prefer
to provide generators of the superspace group, then: the number of generators
is given first, which can not be neglected and must equal the number of
the matrices listed below.
KN
indicating
that the phase (listed in the same line of the preceding column) is known
or not
0: unknown,
its value is to be derived, the listed value will NOT take part in the
derivation, however in the case of STATUS=1 listed
phases will be used to compare with DIMS-derived ones.
1: known,
it will be used as starting phase to derive unknown phases.
2: assign
a random phase value
MK
indicating
that the reflection is neglected or not in the phasing procedure
-1: neglected, and
a random phase is given to this reflection in the output.
1: not neglected.
DN
for STATUS=1,
indicating the difference between the given and the derived phases.