Interface to DKH by A. Wolf, M. Reiher, and B. A. Hess¶

Code author: Justin M. Turney

Section author: Justin M. Turney

Module: Keywords, Samples

Installation¶

Binary

DKH is available as a conda package for Linux and macOS (and Windows, through the Ubuntu shell).
If using the PSI4 binary, dkh has already been installed alongside.
If using PSI4 built from source, and anaconda or miniconda has already been installed (instructions at Quick Installation), dkh can be obtained through conda install dkh -c psi4. Then enable it as a feature with ENABLE_dkh, hint its location with CMAKE_PREFIX_PATH, and rebuild PSI4 to detect dkh and activate dependent code.

To remove a conda installation, conda remove dkh.

Source

If using PSI4 built from source and you want dkh built from from source also, enable it as a feature with ENABLE_dkh, and let the build system fetch and build it and activate dependent code.

Input¶

For all electron calculations one can use the Douglas-Kroll-Hess (DKH) Hamiltonian to take into account scalar relativistic effects.

Minimal input for DKH single-point computation looks like this:

molecule {
Mg
}

set basis aug-cc-pvdz-dk
set relativistic dkh

energy('scf')

By default a 2nd-order DKH calculation is performed. To change the default order use the DKH_ORDER option. The version of the code found in PSI4 is capable of up to 4th-order DKH calculations.

Keywords¶

RELATIVISTIC ¶

Relativistic Hamiltonian type

Type: string

Possible Values: NO, X2C

Default: NO

DKH_ORDER ¶

Order of Douglas-Kroll-Hess

Type: integer

Default: 2

Reference¶

When using this code please make reference to the appropriate following paper:

“The Generalized Douglas-Kroll Transformation,” A. Wolf, M. Reiher, and B. A. Hess, J. Chem. Phys. 117, 9215 (2002). (doi: 10.1063/1.1515314)

How to configure dkh for building Psi4¶

Role and Dependencies

Role — In PSI4, DKH is a library that provides additional quantum chemical capabilities (relativistic effects).
Downstream Dependencies — PSI4 (\(\Leftarrow\) optional) dkh
Upstream Dependencies — dkh \(\Leftarrow\) Fortran

CMake Variables

ENABLE_dkh — CMake variable toggling whether Psi4 builds with dkh
CMAKE_PREFIX_PATH — CMake list variable to specify where pre-built dependencies can be found. For dkh, set to an installation directory containing include/DKH/DKH_MANGLE.h
dkh_DIR — CMake variable to specify where pre-built dkh can be found. Set to installation directory containing share/cmake/dkh/dkhConfig.cmake
CMAKE_DISABLE_FIND_PACKAGE_dkh — CMake variable to force internal build of dkh instead of detecting pre-built
CMAKE_INSIST_FIND_PACKAGE_dkh — CMake variable to force detecting pre-built dkh and not falling back on internal build

Examples

Build bundled

>>> cmake -DENABLE_dkh=ON

Build without dkh

>>> cmake

Link against pre-built

>>> cmake -DENABLE_dkh=ON -DCMAKE_PREFIX_PATH=/path/to/dkh/root

>>> cmake -DENABLE_dkh=ON -Ddkh_DIR=/path/to/dkh/configdir

Build bundled despite pre-built being detectable

>>> cmake -DENABLE_dkh=ON -DCMAKE_PREFIX_PATH=/path/to/unwanted/dkh/root/and/wanted/other/dependencies/root -DCMAKE_DISABLE_FIND_PACKAGE_dkh=ON