From the reference 1H spectrum create a new dataset with edc or iexpno and change the pulse program to pulprog t1ir. All required parameters are as described for the 1H spectrum. The inversion-recovery experiment is recorded as a 2D data set in which a delay (vd) is varied over the course of the experiment. For this reason, change parmod to 2D in eda. A 1D 1H spectrum is obtained for each value of vd that can be readed using the corresponding rser command. Otherwhise, a standard parameter set called PROTONT1 is also available.MODIFY SPECIFIC PARAMETERS
Define a vd-list by typing, for instance, edlist vd t1delay. Enter the desired delays (in seconds) as, for instance:ACQUISITION10sand include it in the acquisition parameters by typing vdlist t1delay.
It is very important to use a long recycle delay, usually d1=5*T1(1H) (d1=10 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=4).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=1 Hz). More details in T1 calculation.PLOT
Use XWINPLOT. Alternatively, plot can be performed using the edg page layout and plot commands.AUTOMATION
It is advisable to store all acquisition and processing parameters (for instance, with the command wpar t1ir all) to be used later.OTHER RELATED VERSIONS
Both acquisition and processing steps can be performed using predefined automated AU programs. Thus, from the standard PROTONT1 parameter set, data acquisition is executed with the xaua command (the program executes the AU program defined in the acquisition parameters AUNM, by default au_zg), and the data can be automatically processed and plotted with the xaup command (the program executes the AU program defined in the processing parameters AUNMP, by default proc_2dt1 ).
More detailed description of the acquisition, processing anf T1 calculation steps in the AVANCE USER's GUIDE, chapter 7: Measuring T1.
The same experiment using a fix interpulse delay is also available (pulprog t1ir1d) to be used by the au-program invrec_au.
Also see: 13C T1 measurements using the Inversion-Recovery experiment