Step 8. Remainder of the QMMM key block

The ADF QM/MM input is almost complete. Now only a few settings need to be defined in the QMMM key block. The remainder of the QMMM key block is given below.

 FORCEFIELD_FILE /usr/bob/QMMM_data/amber95.ff
 RESTART_FILE mm.restart
 OUTPUT_LEVEL=1
 WARNING_LEVEL=2

The FORCEFIELD_FILE defines the filename of the force field file to be used. If the force field file is not in the running directory of the ADF job, then the full path needs to be specified. The RESTART_FILE specifies the name of the QM/MM restart to be written. If the job is a restart itself, this keyword also specifies the QM/MM restart file to read.

The OUTPUT_LEVEL specifies how much output to print during the course of the ADF QM/MM run. OUTPUT_LEVEL=1 is good for most purposes. Using an OUTPUT_LEVEL=2 is good when trouble shooting, but probably provides too much output when the job is running normally. The WARNING_LEVEL keyword specifies when to stop the job. When it is set to 2, the run stops at any spot where a potential QM/MM problem is detected. This is good when first setting up a job because the program attempts to point out potential problems.