Varian Solid-State NMR - HAHNCP1-Spin 1;2 Echo Sequence with CP; Figure 52. HAHNCP1 Pulse Sequence

6.23 HAHNCP1—Spin 1/2 Echo Sequence with CP
01-999162-00 C0402 VNMR 6.1C User Guide: Solid-State NMR 116
Reference
Torchia, D. A. J. Magn. Reson. 1978, 30, 613.
6.23 HAHNCP1—Spin 1/2 Echo Sequence with CP
The HAHNCP1 pulse sequence provides a 90 - tau - 180 - tau Hahn spin echo. If
xpol='y', the initial 90
° pulse is replaced by cross-polarization. If xpol='n', the spin
echo sequence is done.
Use HAHNCP1 to obtain static lineshape for spin-1/2 powder spectra to avoid pulse ring
down and first order ('lp') phase correction of the lineshape. Values of tau1 and tau2
as short as 10 microseconds can be used. Set tau2 less than tau1 to observe the spin echo
and process data with lsfid less than 0 to begin acquisition at the top of the spin echo.
The phase cycle is that of Rance and Byrd. Figure 52 shows a diagram of the HAHNCP1
sequence.
Applicability
HAHNCP1 is available only on
UNITY
INOVA and UNITYplus. It is found in userlib.
Macro
The macro hahncp1 converts a parameter set obtained by XPOLAR or XPOLAR1, for
the spin echo experiment. Observe and decoupler power levels and the 90
° pulse width are
retained, as well as the value of xpol. By default, pwx=pw. Fine calibration of pwx is
recommended, tau1=tau2=10 (in microseconds).
Figure 52. HAHNCP1 Pulse Sequence
pw
cntct
cntct
(tpwrm)
(crossp)
(dipolr)
Tx
Dec
at
d1
AC
tau1
C
tau2
B
2*pwx
<if xpol='y'>