Setup
User Manual Version 002 BRUKER BIOSPIN 159 (327)
Data Acquisition 12.2.1
Setup of the 2D data set:
After the optimization as described above type iexpno to create a new data set,
afterwards switch to 2D data mode by using the “123” button. Set the time domain
for the F1-Dimension according to the maximum desired evolution time of the final
REDOR curve. To calculate the value for td1 you have to keep in mind that the
REDOR–Program is organized in multiples of two rotation periods (compare with
the pulse program scheme).E.g. for a given MAS rate of 10 kHz and a desired
overall evolution time of 10 ms you have to set td1 to a value of 200. This will re-
cord 100 sets of S
0
and S’ experiments with an maximum evolution time in the last
two data rows of the desired 10 ms. The pulse program library supplies the follow-
ing REDOR sequences:
cpredor: standard REDOR for dipolar couplings > 500 Hz, incrementing in 2 rotor
period intervals. Two data sets are required with pl3 set for pulsing (REDOR ex-
periment) or no pulse (=120 dB, reference experiment).
cpredori: stores these data sets in the 2D data frame by interleaving scans of the
S
0
and S’ experiments for the same evolution period (see Figure 12.2.).
cpredorxy8: increments in units of 16 rotor periods, for small couplings. Here the
XY-8 scheme is used for recoupling pulses which is insensitive to offsets. While in
cpredor and cpredori the p pulses should be executed close to resonance, this is
not required nor desired in the XY-8 version because the offset dependence is
well compensated.
Additionally to the cross-polarization pulse programs all REDOR sequences also
exist as a direct excitation version without a cp-Step. These are the programs re-
dor, redori and redorxy8. The setup procedure of these sequences is identical to
the ones explained earlier, but you can skip the CP optimization procedure, which
is replaced by a p/2 pulse on the observe channel.
pl12 adequate power level
1
H decoupling
pl3 adequate power level for f3 π pulse
pl22 120 power level in S
0
experiment for the recoupling
pulses
spnam0 ramp ramp file name for CP
td(f1) 32-256 depending on coupling
aq 20-40 msec acquisition time in f2
ns 8 number of scans per experiment
fnmode QF phase correction mode in the f1 dimension
rg 16-64 receiver gain level
digmod baseopt or digital digitizing mode
Table 12.1. Acquisition Parameters for a
13
C observed C/N REDOR
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