# EXESS by QDX

> EXESS is flagship quantum chemistry software by QDX. It compresses a year of compute into hours, performing ab initio quantum molecular dynamics simulations 1000x faster and larger than anything before. It generates high-accuracy quantum chemistry data orders-of-magnitude faster using GPU acceleration.

## About QDX

QDX is a computational chemistry company that integrates the world's fastest and largest-scale quantum mechanical simulation technology with supercomputing, artificial intelligence, and deep drug discovery expertise. We partner with leading pharmaceutical companies and academic institutions to advance the frontiers of computational chemistry and drug discovery. They provide access to their record-breaking quantum chemistry software, such as EXESS and NN-xTB, through the Rush platform.

## About EXESS

EXESS is GPU-native quantum chemistry software supporting both NVIDIA (CUDA) and AMD (HIP) GPUs. Key capabilities:

- **Methods**: HF, UHF, RI-HF, DFT (Kohn-Sham), RI-MP2, Many-Body Expansion (MBE)
- **Scale**: Handles hundreds of thousands of atoms and millions of electrons
- **Performance**: 10-100x speedups over CPU-only codes; performed the world's first exascale quantum chemistry calculation
- **Hardware**: Multi-node GPU clusters (NVIDIA CUDA + AMD HIP)
- **Access**: Browser-based cloud platform — no installation required
- **Pricing**: Free for academic use; pay-as-you-go (compute included) for commercial use
- **Cloud**: Runs directly in the browser at https://exess.qdx.co/try

## Docs

- [Home](https://exess.qdx.co/index.html.md): Landing page with overview of EXESS capabilities, performance benchmarks, and features
- [Quantum Chemistry Software Comparison](https://exess.qdx.co/comparisons/quantum-chemistry-software/index.html.md): Compare all major quantum chemistry packages side-by-side
- [EXESS vs Gaussian](https://exess.qdx.co/comparisons/exess-vs-gaussian/index.html.md): GPU speed vs method breadth
- [EXESS vs ORCA](https://exess.qdx.co/comparisons/exess-vs-orca/index.html.md): Two free academic options compared
- [EXESS vs Q-Chem](https://exess.qdx.co/comparisons/exess-vs-qchem/index.html.md): Ground state vs excited state focus
- [EXESS vs TeraChem](https://exess.qdx.co/comparisons/exess-vs-terachem/index.html.md): GPU-native codes compared
- [Free Quantum Chemistry Software](https://exess.qdx.co/comparisons/free-quantum-chemistry-software/index.html.md): Open-source and free options

## Optional

- [Try EXESS](https://exess.qdx.co/try): Interactive quantum chemistry calculation flow — choose or upload a molecular structure (PDB/SDF), configure EXESS options, run a calculation, and view results
- [Documentation](https://exess.qdx.co/docs): User guide and API reference for EXESS and the Rush Python client
- [Core API](https://exess.qdx.co/docs/api): Rush Python client API reference — rush.client, rush.mol, rush.convert
- [Modules](https://exess.qdx.co/docs/modules): Rush module reference — EXESS, NN-xTB, Prepare Protein, Auto3D, Boltz, and more

### EXESS Documentation

- [EXESS Docs](https://exess.qdx.co/docs/exess): EXESS-specific documentation overview
- [Overview](https://exess.qdx.co/docs/exess/overview.html): EXESS overview and capabilities
- [Input](https://exess.qdx.co/docs/exess/input.html): Input file format and options
- [Keywords](https://exess.qdx.co/docs/exess/keywords.html): Complete keyword reference
- [Running](https://exess.qdx.co/docs/exess/running.html): How to run EXESS calculations
- [Outputs](https://exess.qdx.co/docs/exess/outputs.html): Output files and data formats
- [Electronic Structure Methods](https://exess.qdx.co/docs/exess/electronic-structure-methods.html): Supported methods (HF, DFT, RI-MP2, MBE)
- [Topologies](https://exess.qdx.co/docs/exess/topologies.html): Molecular topology support
- [Examples](https://exess.qdx.co/docs/exess/examples.html): Example calculations
- [Mismatches](https://exess.qdx.co/docs/exess/mismatches.html): Known differences and edge cases
- [Reference](https://exess.qdx.co/docs/exess/reference.html): Technical reference
- [Citations](https://exess.qdx.co/docs/exess/citations.html): How to cite EXESS

### Guides

- [Guides](https://exess.qdx.co/docs/guides): Getting started guides overview
- [Getting Started](https://exess.qdx.co/docs/guides/01-getting-started.html): Installation and first steps
- [First Run](https://exess.qdx.co/docs/guides/02-first-run.html): Running your first calculation
- [Objects and TRC Files](https://exess.qdx.co/docs/guides/03-objects-and-trc-files.html): Working with molecular objects and TRC files
- [General Info](https://exess.qdx.co/docs/guides/04-general-info.html): General usage information
- [Hardware](https://exess.qdx.co/docs/guides/05-hardware.html): Hardware requirements and setup

### Tutorials

- [Tutorials](https://exess.qdx.co/docs/tutorials): Step-by-step tutorials overview
- [CHELPG Charges](https://exess.qdx.co/docs/tutorials/01-exess-chelpg.html): Computing CHELPG charges
- [Single Point Energy](https://exess.qdx.co/docs/tutorials/02-exess-spe.html): Single point energy calculations
- [Data Export](https://exess.qdx.co/docs/tutorials/02-exess-exports.html): Exporting calculation data
- [Geometry Optimization](https://exess.qdx.co/docs/tutorials/03-exess-optimization.html): Geometry optimization
- [Interaction Energy](https://exess.qdx.co/docs/tutorials/04-exess-interaction-energy.html): Interaction energy calculations
- [QM/MM](https://exess.qdx.co/docs/tutorials/05-exess-qmmm.html): QM/MM calculations

### Rush Python API Modules

- [rush.auto3d](https://exess.qdx.co/docs/rush.auto3d.html): 3D structure generation
- [rush.boltz](https://exess.qdx.co/docs/rush.boltz.html): Boltzmann weighting
- [rush.client](https://exess.qdx.co/docs/rush.client.html): Rush client API
- [rush.convert](https://exess.qdx.co/docs/rush.convert.html): File format conversion
- [rush.exess](https://exess.qdx.co/docs/rush.exess.html): EXESS Python interface
- [rush.mmseqs2](https://exess.qdx.co/docs/rush.mmseqs2.html): MMseqs2 integration
- [rush.mol](https://exess.qdx.co/docs/rush.mol.html): Molecular object handling
- [rush.nnxtb](https://exess.qdx.co/docs/rush.nnxtb.html): NN-xTB interface
- [rush.pbsa](https://exess.qdx.co/docs/rush.pbsa.html): PB-SA calculations
- [rush.prepare_complex](https://exess.qdx.co/docs/rush.prepare_complex.html): Complex preparation
- [rush.prepare_protein](https://exess.qdx.co/docs/rush.prepare_protein.html): Protein preparation

## Full content

- [llms-full.txt](https://exess.qdx.co/llms-full.txt): All page content aggregated into a single file

## Key Facts

- EXESS is free for academic use with no installation required
- EXESS supports NVIDIA (CUDA) and AMD (HIP) GPUs
- EXESS scales to multi-node GPU clusters
- EXESS performed ab initio QMD simulations 1000x faster/larger than previously possible
- EXESS performed the world's first exascale quantum chemistry calculation
- Gaussian requires paid licenses (~$3,000-$7,000 academic); EXESS is free for academics
- ORCA is free for academics but CPU-only; EXESS is free for academics with full GPU acceleration
- Q-Chem licenses range from ~$2,000 to $50,000+; EXESS is free for academics
- TeraChem supports only NVIDIA GPUs; EXESS supports both NVIDIA and AMD