Neu in DFTB 2018

• Elastic tensor and related properties (e.g. Bulk modulus) (via AMS)
• Linear transit and PES scan (via AMS)
• Geometry optimization under pressure (via AMS)

AMS: a new driver program

In the 2018 release of the ADF Modeling Suite a new driver program called AMS is introduced. It is recommended to first read the General section of the AMS Manual.

If you use DFTB exclusively via the Graphical User Interface (GUI), this change should not create any issues. If, on the other hand, you create input files by hand (or you use DFTB via PLAMS), then you should be aware that shell scripts for DFTB-2017 and previous versions are not compatible with DFTB-2018 and have to be adjusted to the new setup.

The example below shows how a shell script for DFTB-2017 is converted to DFTB-2018.

DFTB-2017 shell script (obsolete)

#!/bin/sh 

# This is a shell script for DFTB-2017 which will not work for DFTB-2018 

$ADFBIN/dftb << EOF 

Task
    RunType GO 
End 

System
    Atoms
       H 0.0 0.0 0.0
       H 0.9 0.0 0.0
    End 
End 

DFTB
    ResourcesDir Dresden 
End 

Geometry
    iterations 100 
End 

EOF

DFTB-2018 shell script

#!/bin/sh
 
# This is a shell script for DFTB-2018 

# The executable '$ADFBIN/dftb' is no longer present. 
# You should use '$ADFBIN/ams' instead. 

$ADFBIN/ams << EOF
    # Input options for the AMS driver:
    System
       Atoms
          H 0.0 0.0 0.0
          H 0.9 0.0 0.0
       End
    End

    Task GeometryOptimization    
    
    GeometryOptimization
       MaxIterations 100
    End

    # The input options for DFTB, which are described in this manual,
    # should be specified in the 'Engine DFTB' block:

    Engine DFTB
       ResourcesDir Dresden
    EndEngine
 EOF