OpenThermo User Manual

OpenThermo is a comprehensive C++17 program for calculating molecular thermochemistry properties from quantum chemistry output files (Gaussian, Orca, GAMESS, NWCHEM, CP2K, VASP, Q-Chem). OpenThermo implements state-of-the-art methods for computing thermodynamic quantities including Gibbs free energy, enthalpy, entropy, and heat capacities using statistical mechanics.

Overview

OpenThermo provides a comprehensive suite of tools for molecular thermochemistry calculations:

• Multi-format Support: Gaussian, ORCA, GAMESS-US, NWChem, CP2K, VASP, Q-Chem

• Advanced Thermochemistry: Standard RRHO and quasi-RRHO treatments for low-frequency modes

• Statistical Mechanics: Rigorous implementation of partition functions and thermodynamic properties

• Symmetry Analysis: Automatic point group detection and rotational symmetry number calculation

• High Performance: Optimized C++17 implementation with optional OpenMP parallelization

• Batch Processing: Multi-file analysis with ensemble averaging

Key Features

Scientific Capabilities

• Calculate thermodynamic properties (Gibbs free energy, enthalpy, entropy, heat capacity)

• Support for multiple low-frequency treatment methods (RRHO, Truhlar, Grimme, Minenkov, Head-Gordon)

• Automatic symmetry detection and rotational symmetry number calculation

• Temperature and pressure scanning capabilities

Performance & Safety

• OpenMP parallelization for temperature/pressure scans and vibrational calculations

• Auto-strategy selection for optimal parallelization

• HPC-friendly defaults (uses half of physical CPU cores)

• Memory-efficient algorithms for large systems

Workflow Integration

• Command-line interface with extensive options

• Configuration file support (settings.ini)

• Batch processing of multiple files

• Multiple output formats (console, text files, native .otm format)

Getting Started

New to OpenThermo? Start here:

1. Installation Guide - Install the software on your system

2. Usage Guide - Learn how to use all features with examples

3. Developer Guide - Developer guide for contributors

Quick Start

# Basic usage - calculate thermochemistry from Gaussian output
OpenThermo molecule.log

# Custom temperature and pressure
OpenThermo molecule.log -T 300 -P 2.0

# Temperature scan with Grimme's method
OpenThermo molecule.log -T 200 400 25 -lowvibmeth Grimme

# Get help
OpenThermo --help

Important Note

The project is still in the early stage and not fully tested. Therefore, errors and inaccuracy may happen. Users are suggested to check calculated data against original data from outputs of corresponding quantum chemical programs (with default temperature, concentration, and pressure)

A graphical user interface (GUI) version is under development and can be found here: OpenThermoGUI

Contents

User Guide:

• Installation Guide
  • System Requirements
  • Supported Compilers
  • Build Dependencies
• Installation Methods
  • Quick Start Build
  • GNU Make Build System
  • CMake Build System
  • Windows Build (MSYS2/MinGW)
• Post-Build Setup
  • Add OpenThermo to PATH
  • Verification
  • Successful Compilation Output
  • Environment Setup
• Troubleshooting
  • Common Build Issues
  • Runtime Issues
• Performance Optimization
• Testing
• Uninstallation
• Getting Help
• Usage Guide
  • Quick Start
• Command-Line Options
  • Input and Output Options
  • Thermochemistry Options
  • Low Frequency Treatment Options
  • Mass and Symmetry Options
  • Output Control Options
  • OpenMP / Performance Options
  • Help Options
• Configuration Files
  • Configuration File Support
  • Creating Settings File
  • Settings File Format
  • Configuration Parameters
• Input File Formats
  • Supported Formats
  • File Detection
• Output Files and Formats
  • Console Output
  • Generated Files
• Thermochemistry Calculation Methods
  • Standard RRHO Model
  • Quasi-RRHO Treatments
• Usage Examples
  • Basic Calculations
  • Advanced Calculations
  • Batch Processing Examples
  • Settings File Examples
• Advanced Features
  • Temperature and Pressure Scanning
  • Mass Modifications
  • Symmetry Analysis
  • Imaginary Frequency Handling
  • VASP Energy Selection
  • Batch Processing
• Troubleshooting
  • Common Issues
  • Performance Issues
  • Validation

Developer Guide:

• Developer Guide
• Project Overview
  • Architecture
  • Key Components
  • Key Design Principles
• Development Setup
  • Prerequisites
  • Getting the Source Code
  • Building for Development
  • Testing
  • Code Quality Tools
  • Documentation
• Coding Standards
  • Code Style
  • Documentation Standards
  • Error Handling
  • Memory Management
  • Thread Safety
• Contributing
  • Development Workflow
  • Pull Request Guidelines
  • Code Review Process
• Testing Guidelines
  • Unit Testing
  • Integration Testing
  • Performance Testing
• Continuous Integration
  • CI/CD Pipeline
• Release Process
  • Version Numbering
• Support and Communication

API Reference:

• OpenThermo API
  • Class Hierarchy
  • File Hierarchy
  • Full API

Indices and Tables

• Index

• Module Index

• Search Page

Support & Contributing

For bug reports, feature requests, or questions:

• Issues: GitHub Issues

• Documentation: This user manual

• Help: Use OpenThermo --help for command-line help

License

OpenThermo is released under the MIT License. See the LICENSE file for details.

Version Information

Current Version: v0.001.6

• v0.001.6: Updated version with improved multi-format support and bug fixes

Note

This documentation is for OpenThermo v0.001.6. For older versions, please refer to the archived documentation.