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When linking with LIBXC, the compiler complains about not finding the fortran module libxc_funcs_m.mod
Since LIBXC contains some fortran modules, it should be compiled with the very same fortran compiler as the one used for MOLGW.
For instance, when compiling MOLGW with ifort, LIBXC should have been configured, for instance, as
FC=ifort CC=icc ./configure --prefix=/opt/libxc-3.0.0/
I do not have libtool on my machine, therefore I cannot link MOLGW to libint version 2.1.x
MOLGW works perfectly fine with libint versions 2.0.x or 2.2.x, which do not require libtool.
Compilation of LIBINT is hard. Please help me.
Here is how I compiled LIBINT 2.2.0 on my laptop running on linux Fedora 25:
$ sudo dnf install automake autoconf gcc-c++ boost-devel gmp-devel # to obtain the required packages
Please adapt to your own machine/distribution.
$ tar xzf libint-2.2.0.tgz
$ cd libint-2.2.0
$ mkdir build
$ cd build
$ ../configure --prefix=/opt/libint-2.2.0/ --enable-1body=1 --enable-eri=1 --enable-eri3=1 --enable-eri2=1 --enable-contracted-ints --with-max-am=7 --with-opt-am=2 --with-cxxgen=g++ --with-cxxgen-optflags=-O2 --with-cxx-optflags=-O2
$ make -j 4
$ sudo make install
Running the code
DFT / HF ground-state
BSE / TDDFT calculation
I would like to perform a BSE calculation on top of QSGW, however MOLGW keeps asking for an ENERGY_QP file.
The ENERGY_QP file is meant for one-shot GW runs. In QSGW, it is not needed.
You can cheat on MOLGW by asking to use a tiny scissor shift of the energies so to skip the ENERGY_QP file reading with
The TDDFT calculations are awfully slow.
The construction of the TDDFT kernel is not optimized at all in MOLGW. However you may save much time
by using a smaller integration grid without much loss of accuracy with
TDDFT and BSE solver complains that matrix (A-B) is not positive definite.
If (A-B) is not positive definite, this usual means that the singlet ground-state is metastable against a triplet ground-state.
As a consequence, the BSE or TDDFT will have negative neutral excitations.
Switching on the so-called Tamm-Dancoff approximation with
tda='yes' may numerically solve the problem.
The literature about the singlet/triplet instability is vast in the TDDFT framework.