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Agent skill

Chem Dft Orca Advanced Calculation

by learningmatter-mit in learningmatter-mit/AtomisticSkills

Write and run custom ORCA input files for advanced electronic structure methods or settings not available through the SCINE wrapper, including multi-reference methods, excited states, relativistic…

MITAuto-check passed

Install Chem Dft Orca Advanced Calculation

skills CLI
$ npx skills add learningmatter-mit/AtomisticSkills --skill chem-dft-orca-advanced-calculation -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install learningmatter-mit/AtomisticSkills chem-dft-orca-advanced-calculation --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/learningmatter-mit/AtomisticSkills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/chem-dft-orca-advanced-calculation .claude/skills/chem-dft-orca-advanced-calculation && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
chem-dft-orca-advanced-calculation
GitHub stars
176
Token cost
~2.3k tokens
SKILL.md length
754 words
Files
5 (incl. scripts)
Skills in repo
129
Repo updated
First seen
Licence
MIT

At a glance

Write and run custom ORCA input files for advanced electronic structure methods or settings not available through the SCINE wrapper, including multi-reference methods, excited states, relativistic…

  • Works in 5 steps: Prerequisites → Workflow → Common Use Cases → …
  • SKILL.md covers Goal, 1. Prerequisites, 2. Workflow and 3. Common Use Cases, plus 3 more sections
  • Runs Python scripts from its folder

What it does

Chem Dft Orca Advanced Calculation is an agent skill from learningmatter-mit/AtomisticSkills. Write and run custom ORCA input files for advanced electronic structure methods or settings not available through the SCINE wrapper, including multi-reference methods, excited states, relativistic effects, advanced SCF, NMR/EPR, and more.

Its SKILL.md is about 2.3k tokens, which your agent loads only when the skill is triggered. The skill folder holds 6 other files, including scripts (for example `example/README.md`, `scripts/parse_orca_output.py` and `scripts/run_orca_input.py`).

The repository describes itself as: Integrating AtomisticSkills into Agentic IDEs (Cursor, Claude Code, Codex, Google Antigravity, Hermes Agent, etc). The licence is MIT.

Example prompts

  • “/chem-dft-orca-advanced-calculation”

Requirements

  • Python 3

Workflow steps

5 steps, taken from the step headings in SKILL.md.

  1. Prerequisites
  2. Workflow
  3. Common Use Cases
  4. Output Files
  5. Constraints

What it can do on your machine

Read from SKILL.md and the folder at commit 6257444. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Ships 2 files in scripts/ (Python), which the agent can run.

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    Links to these hosts (documentation or services it may open):

    • faccts.de
    • doi.org
    • github.com

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Chem Dft Orca Advanced Calculation loads about 2.3k tokens when it runs. Until then it costs about 68 tokens; SKILL.md has 754 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~68
When it runs · the whole SKILL.md, loaded when a task matches
~2.3k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.

SKILL.md

The full file from learningmatter-mit/AtomisticSkills at commit 6257444, republished under its MIT licence (© learningmatter-mit). 754 words, ~2,251 tokens.

Download SKILL.mdSave it as .claude/skills/chem-dft-orca-advanced-calculation/SKILL.md (or your agent's skills folder). This skill also uses 4 other files; get the full folder from GitHub.
name
chem-dft-orca-advanced-calculation
description
Write and run custom ORCA input files for advanced electronic structure methods or settings not available through the SCINE wrapper, including multi-reference methods, excited states, relativistic effects, advanced SCF, NMR/EPR, and more.
metadata.category
chemistry
metadata.venv
cpu

Advanced ORCA Calculation

Goal

Enable advanced ORCA quantum chemistry calculations by constructing a custom ORCA input file from scratch. This skill covers methods and features not available through the SCINE wrapper, including multi-reference methods, excited states, relativistic effects, advanced SCF settings, NMR/EPR properties, and more.

[!IMPORTANT] For standard DFT single-point calculations (energy, gradients, Hessian), use the singlepoint skill instead. For geometry optimization, use the optimization skill. This skill is for cases where those wrappers do not expose the needed method or settings.

1. Prerequisites

  • Environment: cpu (commands run through venv/run cpu ...), which includes ase (SCINE not required for this skill)
  • ORCA binary: The environment variable ORCA_BINARY_PATH must point to the ORCA executable
    bash
    export ORCA_BINARY_PATH=/path/to/orca
  • ORCA documentation: Consult the ORCA 6.1 tutorials for method-specific input syntax, keyword blocks, and recommended settings

2. Workflow

Step 1: Understand the user's request

Identify the target method, property, and system. Determine which ORCA keywords and blocks are needed. If unsure, consult the tutorials linked above for the specific method.

Step 2: Write the ORCA input file

Create a .inp file following ORCA input syntax. Every input file should include:

Mandatory elements:

  • A keyword line starting with ! specifying the method, basis set, and job type
  • A *xyzfile entry referencesing an external .xyz file

Strongly recommended elements:

  • %pal nprocs N end: parallelization (always set this to avoid single-core runs)
  • %maxcore M: memory per core in MB (e.g. 4000 for 4 GB per core)

Example — TD-DFT excited states:

! B3LYP def2-TZVP TightSCF
%pal nprocs 4 end
%maxcore 4000

%tddft
  NRoots 10
  MaxDim 5
end

* xyzfile 0 1 molecule.xyz

Example: DLPNO-CCSD(T) single point:

! DLPNO-CCSD(T) def2-TZVPP def2-TZVPP/C TightSCF
%pal nprocs 8 end
%maxcore 4000

* xyzfile 0 1 molecule.xyz

Example: Geometry optimization with frequency calculation:

! B3LYP def2-TZVP D3BJ Opt Freq TightSCF
%pal nprocs 4 end
%maxcore 4000

* xyzfile 0 1 molecule.xyz

Example: CASSCF multi-reference:

! CASSCF def2-TZVP
%pal nprocs 4 end
%maxcore 8000

%casscf
  nel 6
  norb 6
  nroots 3
end

* xyzfile 0 1 molecule.xyz

[!TIP] When using an external .xyz file with * xyzfile charge mult filename.xyz, the .xyz file must be placed in the same directory where ORCA runs (the --output_dir).

Step 3: Run the calculation
bash
${CLAUDE_SKILL_DIR}/../../venv/run cpu python ${CLAUDE_SKILL_DIR}/scripts/run_orca_input.py \
    --input_file calculation.inp \
    --output_dir research/my_project/advanced_calc

The script will:

  1. Validate basic input structure and warn about missing %pal/%maxcore
  2. Copy the input file to the output directory
  3. Execute ORCA and capture all output
  4. Parse the final electronic energy from the output
  5. Save a calculation_results.json summary
Step 4: Parse results

For standard energies, the runner script already extracts the final energy. For other properties, use the dedicated parser:

bash
${CLAUDE_SKILL_DIR}/../../venv/run cpu python ${CLAUDE_SKILL_DIR}/scripts/parse_orca_output.py \
    --output_file research/my_project/advanced_calc/calculation.out \
    --property energy orbitals

Available --property options in the parser:

  • energy: Final energy, nuclear repulsion, dispersion correction
  • orbitals: Orbital energies, HOMO/LUMO, gap
  • frequencies: Vibrational frequencies, imaginary modes, IR intensities
  • thermochemistry: ZPE, enthalpy, Gibbs energy, entropy
  • all: Parse everything available
Step 5: Manual output inspection

For properties not covered by the built-in parser (excited-state energies, NMR shifts, spin populations, natural orbitals, etc.), read the ORCA calculation.property.txt file directly.

Show full SKILL.md (343 more words)Show less

3. Common Use Cases

MethodKey ORCA KeywordsNotes
Multi-step SCF convergence! GuessMode=CMatrixSome SCFs are difficult to converge, solving it multiple steps, converging first on a small basis set and loose criterion and launching it again with the desired parameters
TD-DFT excited states! B3LYP def2-TZVP, %tddft NRoots N endUse TDA for faster approximation
CASSCF/NEVPT2! CASSCF def2-TZVP, %casscf nel N norb M endActive space selection is critical
DFT + NMR! B3LYP def2-TZVP NMRShielding tensors in output
DFT + EPR! B3LYP def2-TZVP EPR/ORPg-tensor and hyperfine couplings
Relativistic (ZORA)! B3LYP ZORA def2-TZVP SARC/JFor heavy elements; use SARC basis sets
Scan/Relaxed scan! B3LYP def2-SVP Opt, %geom Scan ... endPotential energy surface scans

4. Output Files

  • calculation_results.json: Summary with energy, SCF convergence, return code, and any input warnings
  • <input_stem>.property.txt: Structured ORCA output file of all properties
  • <input_stem>.out: Full ORCA output file, only suitable for debugging errors
  • Various ORCA-generated files (.gbw, .densities, .engrad, etc.) in the output directory
  • parsed_results.json (if parser was run): Structured extraction of requested properties

5. Constraints

  • Input correctness: The agent is responsible for writing a valid ORCA input file. The runner performs basic validation but cannot catch all syntax errors, ORCA itself will report those in the output.
  • SCF convergence: Always check that the SCF converged. If it did not, try SlowConv, VerySlowConv, or adjust %scf MaxIter and damping settings.
  • Memory: ORCA can be memory-intensive for correlated methods. Set %maxcore appropriately (rule of thumb: total available RAM / nprocs, leaving some for the OS).
  • Disk: Post-HF methods (CCSD(T), CASSCF) can generate large temporary files. Ensure sufficient disk space.
  • ORCA binary: ORCA_BINARY_PATH must be set and point to a working ORCA installation.
  • Environment: All commands require the cpu environment.
  • Parallelization: ORCA uses OpenMPI internally. Do not run multiple ORCA instances on overlapping core sets.
  • Output parsing: The built-in parser covers common output patterns. For uncommon methods or output formats, the raw .out file must be inspected directly.

References

Author: Miguel Steiner Contact: GitHub @steinmig

© learningmatter-mit, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 4 other files (scripts) in skills/chem-dft-orca-advanced-calculation of learningmatter-mit/AtomisticSkills.

  • SKILL.md
  • example/README.md
  • example/h2o.xyz
  • scripts/parse_orca_output.py
  • scripts/run_orca_input.py

Open the folder on GitHubat commit 6257444

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Questions about Chem Dft Orca Advanced Calculation

What does Chem Dft Orca Advanced Calculation do?

Write and run custom ORCA input files for advanced electronic structure methods or settings not available through the SCINE wrapper, including multi-reference methods, excited states, relativistic…. Chem Dft Orca Advanced Calculation is an agent skill from learningmatter-mit/AtomisticSkills. Write and run custom ORCA input files for advanced electronic structure methods or settings not available through the SCINE wrapper, including multi-reference methods, excited states, relativistic effects, advanced SCF, NMR/EPR, and more.

How do I install Chem Dft Orca Advanced Calculation in Claude Code?

Run `npx skills add learningmatter-mit/AtomisticSkills --skill chem-dft-orca-advanced-calculation -a claude-code`. Or copy the skill folder (skills/chem-dft-orca-advanced-calculation in learningmatter-mit/AtomisticSkills) into .claude/skills/chem-dft-orca-advanced-calculation in your project. Claude Code loads it when a task matches its description.

How do I install Chem Dft Orca Advanced Calculation in Codex?

Run `npx skills add learningmatter-mit/AtomisticSkills --skill chem-dft-orca-advanced-calculation -a codex`. Or copy the skill folder (skills/chem-dft-orca-advanced-calculation in learningmatter-mit/AtomisticSkills) into .agents/skills/chem-dft-orca-advanced-calculation in your project. Codex loads it when a task matches its description.

Can I use Chem Dft Orca Advanced Calculation in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add learningmatter-mit/AtomisticSkills --skill chem-dft-orca-advanced-calculation -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/chem-dft-orca-advanced-calculation, .gemini/skills/chem-dft-orca-advanced-calculation, .github/skills/chem-dft-orca-advanced-calculation and .opencode/skills/chem-dft-orca-advanced-calculation in your project.

What does Chem Dft Orca Advanced Calculation need to run?

Going by SKILL.md and its folder, Chem Dft Orca Advanced Calculation needs Python for the scripts in its folder. Our summary lists: Python 3.

Does Chem Dft Orca Advanced Calculation access the network?

SKILL.md names 3 domains. As links in the text: faccts.de, doi.org and github.com. This is read from the text; nothing was executed.

Is Chem Dft Orca Advanced Calculation safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. The check reads SKILL.md only: the scripts in the folder are not scanned, so read them before running anything.

What licence does Chem Dft Orca Advanced Calculation use?

Chem Dft Orca Advanced Calculation is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Chem Dft Orca Advanced Calculation use?

About 2.3k tokens (SKILL.md is roughly 9k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Chem Dft Orca Advanced Calculation?

Skills that share tags, products or a category with Chem Dft Orca Advanced Calculation: Desktop Electron (OpenHands/OpenHands, 90k stars), Motion Advanced (affaan-m/ECC, 275k stars), Electron App Automation (vercel-labs/agent-browser, 44k stars) and Orca (alsk1992/CloddsBot, 2.9k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Chem Dft Orca Advanced Calculation?

learningmatter-mit (a GitHub organization) maintains it in learningmatter-mit/AtomisticSkills, which has 176 GitHub stars. The repository holds 129 skills in this directory. The repository was last updated on October 7, 2026.

Source: learningmatter-mit/AtomisticSkills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.