ORCA¶

ORCA is an ab initio quantum chemistry program package that contains modern electronic structure methods including density functional theory, many-body perturbation, coupled cluster, multireference methods, and semi-empirical quantum chemistry methods.

Usage¶

ORCA module¶

ORCA has to be loaded using Lmod prior to running it.

$ module load ORCA

Once the module has been loaded you will need to set some enviroment variables:

You can also list all available versions using Lmod's spider command:

$ module spider ORCA
---------------------------------------------
  ORCA:
---------------------------------------------
    Description:
      ORCA is a flexible, efficient and easy-to-use general purpose tool for quantum 
      chemistry with specific emphasis on spectroscopic properties of open-shell
      molecules. It features a wide variety of standard quantum chemical methods 
      ranging from semiempirical methods to DFT to single- and multireference correlated
      ab initio methods. It can also treat environmental and relativistic effects.

     Versions:
        ORCA/4.0.1.2-OpenMPI-2.0.2
        ORCA/4.2.1-gompi-2019b

---------------------------------------------
  For detailed information about a specific "ORCA" module (including how to load the modules) use the module's full name.
  For example:

     $ module spider ORCA/4.2.1-gompi-2019b
---------------------------------------------

How to run ORCA¶

Submission scripts should contain the following lines to run ORCA:

Batch script for a parallel execution of ORCA using the /lscratch

#!/bin/bash                                                                                                                                                              
#SBATCH --qos=regular
#SBATCH --job-name=ORCA_JOB
#SBATCH --mem=200gb
#SBATCH --cpus-per-task=1
#SBATCH --nodes=1
#SBATCH --ntasks-per-node=36
#SBATCH --output=%x-%j.out
#SBATCH --error=%x-%j.err

export SCRATCH_DIR=/lscratch/$USER/$SLURM_JOB_ID
mkdir -p $SCRATCH_DIR

cd $SLURM_SUBMIT_DIR
cp orca_input.inp $SCRATCH_DIR
cd $SCRATCH_DIR

module load ORCA

$ORCA_DIR/orca orca_input.inp >& $SLURM_SUBMIT_DIR/orca_input.log

rm -rf $SCRATCH_DIR

Batch script for a parallel execution of ORCA using the /scratch

#!/bin/bash                                                                                                                                                              
#SBATCH --partition=regular
#SBATCH --job-name=ORCA_JOB
#SBATCH --mem=200gb
#SBATCH --cpus-per-task=1
#SBATCH --nodes=1
#SBATCH --ntasks-per-node=36
#SBATCH --output=%x-%j.out
#SBATCH --error=%x-%j.err

module load ORCA

$ORCA_DIR/orca orca_input.inp >& orca_input.log