README.md

HITRAN

Spectroscopic data analysis using the HITRAN database.

Overview

This project provides tools for calculating absorption coefficients and visualizing spectral data based on the HITRAN (High-resolution Transmission Molecular Absorption) database.

Requirements

• Python >= 3.12

Installation

uv sync

Project Structure

HITRAN/
├── shared/              # Common utilities
│   ├── constants.py     # Physical constants
│   └── blackbody.py     # Blackbody radiation functions
├── OTM/                 # Planck mean absorption coefficient
├── calc_Lp/             # Planck mean absorption length
└── absorption_spectrum/ # Absorption coefficient plotting

Modules

shared

Common utilities used across modules. Provides physical constants and blackbody radiation functions.

OTM

Calculates Planck mean absorption coefficients from HITRAN spectroscopic data using the SD-Voigt line profile.

See OTM/README.md for details.

cd OTM
uv run main.py

calc_Lp

Calculates Planck mean absorption length using Voigt profile-based absorption coefficients.

Based on: Y. Ju et al., Proceedings of the Combustion Institute 27 (1998), 2691.

See calc_Lp/README.md for details.

cd calc_Lp
uv run main.py

absorption_spectrum

Plots wavenumber-dependent absorption coefficients for molecular species. Supports CSV output.

cd absorption_spectrum
uv run main.py

Supported Species

Molecule	HITRAN ID
H2O	1
CO2	2
CO	5
CH4	6
NO	8
N2O	4
NH3	11
H2O2	25
H2CO	20
HONO	42
SF6	30

References

• Y. Ju, H. Guo, K. Maruta, and F. Liu, "On the extinction limit and flammability limit of non-adiabatic stretched methane-air premixed flames," Journal of Fluid Mechanics 342 (1997), 315-334.
• Y. Ju, K. Maruta, and T. Niioka, "Combustion limits," Applied Mechanics Reviews 53 (2000), 257-277.
• HITRAN Database: https://hitran.org/

License

This project is licensed under the zlib License. See LICENSE for details.