From the reference 13C spectrum create a new dataset with edc and change the pulse program to pulprog t1irpg. All other parameters as in the 13C spectrum. This experiment is recorded as a 2D data set (change parmod to 2D in eda) in which a delay (vd) is varied over the course of the experiment. A 1D 13C spectrum is obtained for each value of vd that can be readed using the corresponding rser command.MODIFY SPECIFIC PARAMETERS
Define a vd-list by typing, for instance, edlist vd t1cdelay. Enter the desired delays (in seconds) as, for instance:ACQUISITION50sand include it in the acquisition parameters by typing vdlist t1cdelay.
It is very important to use a long recycle delay, usually d1=5*T1(13C) (d1=60 s), and l4=td1 is the number of experiments (or number of delays in vd-list).
Start acquisition by rga and zg (minimum number of scans ns=8 and ds=2).PROCESSING
The spectra can be processed by the automation program proc_t1 or manually entering xf2. In all cases, set SI1 as a power of two greater than or equal to the number of delays in vdlist (SI1=16). A linebroadening is usually applied (lb=2 Hz). To adjust phase, read first spectrum, in which all signals have positive phase, and transfer this phase correction to all other spectra (PH_mod: pk). More details in T1 calculation.PLOT
It is advisable to store all acquisition and processing parameters (for instance, with the command wpar t1irpg all) to be used later.OTHER RELATED VERSIONS
More detailed description of the processing anf T1 calculation steps in the AVANCE USER's GUIDE, chapter 7: Measuring T1 (this file is also available in PDF format).
Also see: 1H T1 measurements using the Inversion-Recovery experiment