• Record a conventional ¹³C spectrum

From the reference ¹³C spectrum create a new dataset with 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.

Define a vd-list by typing, for instance, edlist vd t1cdelay. Enter the desired delays (in seconds) as, for instance:

50s
24s
16s
10s
6s
3s
1s
0.5s
0.05s

and 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).

Minimum number of scans ns=8 and ds=2).

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.

It is advisable to store all acquisition and processing parameters (with the command ) to be used later.

 Also see: ¹H T₁ measurements using the Inversion-Recovery experiment