Editing a Spin System

In NMR-SIM spin systems are defined as a plain ASCII text file and are denoted by the file extension. ham. After the correct installation the spin system files supplied with the program are saved in the sub-directory. .. Ham. Spin systems can be modified like 

Start NMR-SIM, in the main display window the name of the currently selected spin system, if any, is shown. Using the Edit I Spin system 

The labels used in the definition of the NMR-SIM spin system parameters depend to some extent upon personal preference. As with any programming language it is important to include comments comments not only makes the spin system file more readable, they also make it easier to keep track of any modifications to the file and help other users to understand the spin system definitions. Comment lines start with a semicolon ( ) and both the semicolon and the following text are ignored by the NMR-SIM processor. 

The full version of NMR-SIM allows the use of externally defined pulse sequence units e.g. composite pulse decoupling sequences and arrays of constants e.g. delay lists, using pre-processor commands. These pre-processor commands correspond to the standard C pre-processor commands ifdef, if, else, endif and include. Preprocessor commands are not supported by this teaching version and consequently the description of these commands is excluded. For further information on pre-processor commands consult the NMR-SIM manual. 

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