ORCA quantum chemistry¶

Both Easley and Hopper use Slurm (Simple Linux Utility for Resource Management) to submit jobs and manage resources. Below is a sample script for submitting an Orca job named orca_submission.sh.

Submitting an Orca script on Easley¶

#!/usr/bin/bash

## Set your slurm flags here requesting resources.
#SBATCH --job-name=orca_test
#SBATCH --output=test.out
#SBATCH --ntasks=8
#SBATCH --cpus-per-task=1
#SBATCH --partition=general
#SBATCH --mem-per-cpu=6GB
#SBATCH --mail-type=begin        # send email when job begins
#SBATCH --mail-type=end          # send email when job ends
#SBATCH --mail-type=fail         # send email if job fails
#SBATCH --mail-user=<YourNetID>@unm.edu

module load orca/6.1.1

## Set your input and output file names
input_file=my_orca_input.inp
output_file=my_orca_output.log

# Orca needs the full path when running in parallel
full_orca_path=$(which orca)

# Run Orca
$full_orca_path $input_file > $output_file

Now you can simply submit your job to the queue with sbatch orca_submission.sh.

Submitting an Orca script on Hopper¶

The Hopper version is identical — check sinfo for the partitions you have access to (Hopper's default is general, same as Easley):

#!/usr/bin/bash

## Set your slurm flags here requesting resources.
#SBATCH --job-name=orca_test
#SBATCH --output=test.out
#SBATCH --ntasks=8
#SBATCH --cpus-per-task=1
#SBATCH --partition=general
#SBATCH --mem-per-cpu=6GB
#SBATCH --mail-type=begin        # send email when job begins
#SBATCH --mail-type=end          # send email when job ends
#SBATCH --mail-type=fail         # send email if job fails
#SBATCH --mail-user=<YourNetID>@unm.edu

module load orca/6.1.1

## Set your input and output file names
input_file=my_orca_input.inp
output_file=my_orca_output.log

# Orca needs the full path when running in parallel
full_orca_path=$(which orca)

# Run Orca
$full_orca_path $input_file > $output_file

Now you can simply submit your job to the queue with sbatch orca_submission.sh.

Neither Easley nor Hopper provisions a personal top-level scratch directory by default for every user. If you need scratch space for large I/O, use your project's allocated path under /carc/scratch/projects/ (see storage_permissions_BeeGFS.md for how to find your exact path, since the layout varies by project) or just run directly from $SLURM_SUBMIT_DIR, as the scripts above do. Contact help@carc.unm.edu if you need a dedicated scratch allocation.

Module and paths verified against orca/6.1.1 on both Easley and Hopper.

Migrated from UNM-CARC QuickBytes (last source update 2026-08-03). Spotted a problem? Open an issue or pull request.

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