I am doing carbon-13 T1 relaxation time measurements on not too
concentrated samples using the inversion recovery sequence on our
AMX400 spectrometer. In order to compensate for long term
instabilities I modyfied the original pulseprogram in order to cycle
several times through the delay list so that spectra for each delay
arise from different times during the experiment. I added the 3rd
line from the bottom in the folowing pulse program :
;t1irdc.hf
;T1 measurement using inversion recovery
;decoupling during acquisition
;using average cycles
1 ze
d11 s2 cpd
2 d1
3 p2 ph1
vd
p1 ph2
go=2 ph31
d1 iv wr #0 if #0 zd
lo to 3 times l4
d11 rf #0
lo to 3 times l5
do
exit
;hl1: ecoupler high power level
;p1 : 90 degree transmitter high power pulse
;p2 : 180 degree transmitter high power pulse
;d1 : relaxation delay; 1-5 * T1
;d11: delay for disk I/O [30 msec]
;vd : variable delay, taken from vd-list
;l4 : number of values in vd list
;l5 : number of average cycles
The program appears to do what it is supposed to do, however if I try
to predict the time an specific experiment will take using the UXNMR
command expt, the computer always comes up with a time 2-3 h shorter
than the time actually needed. Also the cowntdown of residual
experiment time during the experiment reaches zero several hours
before the experiment is finished.
Is there anything wrong with the change in the pulse sequence I made
or did anybody observe something similar ? I am thankful for any
comments.
Holger Foersterling***************************************
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* Frank-Holger Foersterling *
* Department of Chemistry *
* University of Tennessee *
* Knoxville, TN37996 *
* *
* E-mail : *
* foersterling@novell.chem.utk.edu *
* *
* *
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