Varian Solid-State NMR - HETCORCP1-Solid-State HETCOR

6.6 HETCORCP1—Solid-State HETCOR
01-999162-00 C0402 VNMR 6.1C User Guide: Solid-State NMR 92
6.6 HETCORCP1—Solid-State HETCOR
HETCORCP1 is a
1
H –
13
C heteronuclear chemical shift correlation (HETCOR)
experiment for solid-state materials. Analogous to solution-state HETCOR experiments,
this sequence provides correlation between
1
H and
13
C chemical shifts. The HETCORCP1
experiment differs from the solution-state HETCOR in that correlation depends on dipolar
interactions rather than J coupling.
Applicability
HETCORCP1 is available on
UNITY
INOVA, UNITYplus, and UNITY systems. It is found in
psglib.
Macro
The macro hetcorcp1 converts a parameter set, obtained with XPOLAR or XPOLAR1,
for the solids HETCOR experiment HETCORCP1. Power levels and the proton 90
° pulse
width are retained. Default parameters set up for a phase-sensitive hypercomplex data set
acquisition. The correct sw1 is calculated and srate is set to the preferred value. Set the
actual spin rate equal to srate. A single decoupler offset dof is used throughout.
Parameters
hetcorcp1 uses the
UNITY
INOVA and UNITYplus parameters tpwr, tpwrm, dpwr,
cppwr, dipolr, crossp, dblvl2, pw, and cntct. See page 85 for a description of
these parameters.
setup is set to 'n' to obtain a 2D spectrum (normal operation). Set setup='y' to
obtain a single t
1
FID, blew is the number of BLEW-12 cycles. You may use setup set
to 'y' to obtain a one-dimensional spectrum using a “proton chemical shift selection
pulse” or to observe the pulse sequence with dps for ni greater than 1.
pw is both the
1
H 90° pulse and the
13
C 90° pulse—the pulses must be equal. Adjust
tpwrm (using xpwxcal) to make the pulse lengths equal.
wim is the number of WIM-24 cycles used for cross-polarization. For best results, set the
length of the WIM-24 cross-polarization to occupy one-half a rotor period, for example,
wim=1, pw=4.0, and srate=5208 yields 96 microseconds of CP and a rotor cycle of
192 microseconds.
srate is the actual rotor speed (see wim above). It is preferable, but not necessary, to use
rotor speed control.
bmult is the number of BLEW-12 cycles per f
1
dwell time. Set parameter sw1 to the value
1.0/(bmult*12*pw*1e-6). Default values are bmult=2 for phase=1,2
(hypercomplex), alternatively bmult=1 for phase=3 (TPPI).
phase=1,2 for the hypercomplex method (use wft2da for the 2D FT); phase=3 for
TPPI (use wft2d(1,0,0,0) for the 2D FT).
dipof2 is set to 'y' to use a second decoupler offset during acquisition. dof determines
the f
1
offset, which may be set above or below the
1
H chemical shift region if a pedestal is
present in f
1
. In this case, set dipoff for the center of the
1
H shift region for best
decoupling. dipof2 is set to 'n' to use dof during the evolution period and decoupling.