Well, now you come to the big division among us. Which conventions to use? How did you enter your CSA parameters?

span and skew?

delta and eta?

anisotropy and eta?

you could also try reversing the order of the angles. I have also found that the sign of the CSA could vary between conventions, STARS and SIMPSON for example each use delta but the signs are opposite. Sorry but I'm not sure which parameters DMFIT or WSOLIDS use, but I would guess span and skew.

Cheers,

Andy

__________________________________________________
Andrew S. Lipton Ph. D.
Biological Sciences Division/Cell Biology & Biochemistry Group

FUNDAMENTAL AND COMPUTATIONAL SCIENCES DIRECTORATE 

Pacific Northwest National Laboratory
902 Battelle Boulevard
P.O. Box 999, MSIN K8-98
Richland, WA  99352 USA
Tel:  509-371-6533
Fax: 509-371-6546
as.lipton@pnl.gov
www.pnl.gov

On Feb 27, 2009, at 7:11 AM, mychemistry2001 wrote:

Hi folks,

I am trying to simulate a static spectrum which combines the
second-order quadrupolar coupling and chemical shift anisotropy. I set
the angles for quadrupole to be 0 0 0 and the angles for the shift to
be 70 90 80. However, the simulation gives an unexpected shape which
is different from both the experimental and the DMFIT and the WSOLIDS.
Can anyone help me on this? Thanks a lot.

The input file is as follows:

spinsys {
channels 87Rb
nuclei 87Rb
shift 1 -150p -300p 0.7 70 90 80
quadrupole 1 2 7e6 0.5 0 0 0
}

par {
spin_rate 0
gamma_angles 1
sw 625000
crystal_file zcw4180
np 8192
start_operator I1x
detect_operator I1c
method direct
proton_frequency 600e6
verbose 1101
}

proc pulseq {} {
global par
set dw [expr 1e6/$par(sw)]
acq x
for {set i 1} {$i < $par(np)} {incr i} {
delay $dw
acq x
}

}

proc main {} {
global par tsw

set f [fsimpson]
fsave $f $par(name).fid
fzerofill $f 65536
faddlb $f 120 0
fft $f
fsave $f $par(name).spe
funload $f
}