Hi everyone,
I'm trying to simulate a 2D Heteronuclear Correlation sequence found in this
paper: R. Fu et al 2007, Journal Magnetic Resonance 118 41-48.
I'm using the sequence to simulate the CSA powder patterns for 15N and 1H. The
generated fid when displayed in GSim shows projections that resemble the 15N and
1H CSAs. However the 2D spectrum looks nothing like what I expected, and when
taking individual slices of the spectrum in either the proton or nitrogen
dimension, the 1D slices look nothing like the expected CSA powder patterns. If
anybody could offer me any help, it'll be much appreciated.

Thanks,
Milton Truong

My input file is as follows:

#Test of Fu 2D-HETCOR
spinsys {
channels 1H 15N
nuclei 1H 15N
dipole 1 2 10000 0 0 0
shift 1 9.33p 7.67p 0.65 0 0 0
shift 2 0p 97.7p 0.13 0 0 0
# shift 2 119.3p 97.7p 0.13 0 0 0
}
par {
proton_frequency 400e6
# crystal_file alpha0beta90
crystal_file zcw4180
start_operator I1z
detect_operator I2m
verbose 0100
np 512
ni 128
variable rf 83000
variable t90 0.25e6/rf
variable dpwrlg 83000
variable MSHOTn 4
sw 40000
sw1 dpwrlg*1.5
variable tsw 1.e6/sw
variable tcp 60
variable rf2 sqrt(3/2.)*rf
variable off sqrt(1/2.)*dpwrlg
variable tpwrlg sqrt(3/2.)*dpwrlg
variable dec 130000
}
proc pulseq {} {
global par

#H90
reset
pulse $par(t90) $par(rf) -x 0 0
store 11
reset
pulse $par(t90) $par(rf) -y 0 0
store 12

#MSHOT
set tp [expr $par(tsw)/40.5]
# set tp 4
set td [expr $tp*7/4.]
# set td 5.4
set tp4 [expr $tp*4.]

reset
# turnoff dipole_1_2
for {set i 0} {$i < $par(MSHOTn)} {incr i} {
set ph [expr 120*$i]
delay $td
pulse $tp $par(rf) [expr ( 90+$ph) % 360] 0 0
pulse $tp4 $par(rf) [expr ( 0+$ph) % 360] 0 0
pulse $tp4 $par(rf) [expr (180+$ph) % 360] 0 0
pulse $tp $par(rf) [expr (270+$ph) % 360] 0 0
delay $td
}
store 2

#H90,CP
pulse $par(t90) $par(rf) y 0 0
pulse $par(tcp) $par(rf) x $par(rf2) x
# pulse $par(tcp) $par(rf) x $par(rf) x
store 3

#HET DEC
reset
pulse $par(tsw) $par(dec) x 0 0
store 4

#EXP; States acq
for {set j 0} {$j < [expr $par(ni)/2]} {incr j} {
reset
prop 11
prop 2
store 11
prop 3
acq $par(np) 4

reset
prop 12
prop 2
store 12
prop 3
acq $par(np) 4
}
}
proc main {} {
global par
set f [fsimpson]
fsave $f $par(name).fid