QuasiX
Getting Started
Installation
System Requirements
Operating Systems
Hardware Requirements
Software Requirements
Installation Methods
Method 1: pip install (Recommended)
Method 2: Development Installation
Method 3: Conda Environment
Verifying Installation
Optional Dependencies
Intel MKL
OpenMP Threading
HDF5 Support
Troubleshooting
Rust Compilation Errors
libcint Not Found
Memory Errors
BLAS Threading Conflicts
Platform-Specific Notes
Ubuntu/Debian
macOS
HPC Clusters
Building Documentation
Next Steps
Quick Start Guide
Prerequisites
Example 1: G0W0 Calculation for Water
Example 2: evGW for Better Accuracy
Example 3: BSE Optical Spectrum
Example 4: Custom Calculation Parameters
G0W0 with Custom Frequency Grid
Choosing the QP Solver
Example 5: Parallel Execution
Output Analysis
Accessing Quasiparticle Energies
Self-Energy Analysis
Comparing Starting Points
Common Workflow: GW + BSE
Next Steps
User Guide
Tutorials
Getting Started
Available Tutorials
Basic Tutorials
Basic G0W0 Calculation
Comparing Starting Points
evGW Basics
Advanced Topics
BSE Optical Spectra
Basis Set Convergence
Performance Tuning
Benchmark Reproduction
GW100 Benchmark Guide
Planned Tutorials
Example Gallery
G0W0 Ionization Potential
Optical Gap from BSE
Exciton Binding Energy
See Also
Benchmarks
G₀W₀ Validation: QuasiX vs PySCF
evGW Validation: QuasiX vs Experiment
evGW: QuasiX Newton vs TURBOMOLE Graphical
Performance Benchmarks
evGW Convergence
Data Sources
References
Theory Background
GW Theory
Introduction
Many-Body Perturbation Theory
Starting Point: Green’s Function
The GW Approximation
Quasiparticle Equation
Self-Energy Components
G0W0: One-Shot GW
Workflow
Linearized QP Equation
Newton Solver
evGW: Eigenvalue Self-Consistent GW
Algorithm
Starting Point Dependence
Density Fitting (RI Approximation)
Frequency Integration
Imaginary Frequency Formulation
Analytic Continuation
Frequency Grids
Implementation Details
References
BSE Theory
Introduction
Theoretical Framework
Two-Particle Green’s Function
BSE Hamiltonian
Matrix Elements
Spin Channels
Singlet Excitations
Triplet Excitations
Tamm-Dancoff Approximation (TDA)
Optical Properties
Transition Dipole Moments
Oscillator Strengths
Absorption Spectrum
Exciton Analysis
Exciton Binding Energy
Exciton Wavefunction
Natural Transition Orbitals
Implementation Details
QuasiX Implementation
Computational Workflow
References
API Reference
API Reference
Overview
Core Drivers
Result Objects
Utility Functions
Module Documentation
GW API
G0W0Driver
evGWDriver
G0W0Result
evGWResult
Accessing Detailed Results
See Also
BSE API
BSEDriver
BSEResult
Generating Absorption Spectra
Singlet vs Triplet Excitations
Active Space Truncation
Exciton Analysis
See Also
Driver Modules
Overview
Driver Hierarchy
Typical Workflow
Common Options
Best Practices
Error Handling
Parallelization
Performance Tips
Detailed API
Quick Reference
G0W0Driver
evGWDriver
BSEDriver
Result Attributes
G0W0Result / evGWResult
BSEResult
Error Handling
See Also
Development
Contributing
Ways to Contribute
Development Setup
Prerequisites
Clone and Setup
Build Rust Extension
Code Style
Rust
Python
Testing
Run Tests
Add Tests
Pull Request Process
Commit Message Format
Code Review
Reporting Issues
Bug Reports
Feature Requests
Development Guidelines
Evidence-Based Development
Validation Requirements
Questions?
License
Changelog
[0.6.0] - 2025-12 (M1 Milestone)
Added
Validation
[0.5.0] - 2025-11
Added
Changed
[0.4.0] - 2025-11
Added
Fixed
[0.3.0] - 2025-10
Added
Changed
[0.2.0] - 2025-10
Added
Performance
[0.1.0] - 2025-09
Added
Infrastructure
Version History Summary
Roadmap
See Also
QuasiX
Index
Edit on GitHub
Index
B
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C
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D
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E
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G
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H
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K
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L
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N
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O
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Q
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S
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T
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Z
B
BSEDriver (built-in class)
BSEResult (built-in class)
C
converged (G0W0Result attribute)
convergence_history (evGWResult attribute)
D
dft_energies (G0W0Result attribute)
E
eigenvectors (BSEResult attribute)
evGWDriver (built-in class)
evGWResult (built-in class)
excitation_energies (BSEResult attribute)
G
G0W0Driver (built-in class)
G0W0Result (built-in class)
gap_qp (G0W0Result attribute)
get_spectrum() (BSEDriver method)
H
homo_dft (G0W0Result attribute)
homo_idx (G0W0Result attribute)
homo_qp (G0W0Result attribute)
K
kernel() (BSEDriver method)
(evGWDriver method)
(G0W0Driver method)
L
lumo_idx (G0W0Result attribute)
lumo_qp (G0W0Result attribute)
N
n_iter (evGWResult attribute)
n_states (BSEResult attribute)
O
oscillator_strengths (BSEResult attribute)
Q
qp_energies (G0W0Result attribute)
S
sigma_c (G0W0Result attribute)
sigma_x (G0W0Result attribute)
T
transition_dipoles (BSEResult attribute)
Z
z_factor (G0W0Result attribute)