Overview of HitranLab

Why use HitranLab?

HitranLab is a lightweight macOS application for quickly inspecting and simulating HITRAN .par files without writing code.

It is not intended to replace HITRANonline, HAPI, MODTRAN, or custom research software. Those tools are better suited for advanced modeling, automation, batch processing, and specialized analysis workflows.

HitranLab is designed for fast visual inspection of HITRAN line-by-line data from a native macOS desktop app. It is useful when you want to load a .par file, select molecules, view stick spectra, apply simple broadening, compare absorbance and transmittance, and export results quickly.

Key features

- Load HITRAN-format .par files

- Select molecules, spectral range, and minimum line strength

- Display line-by-line data as stick spectra

- Display simulated spectra as absorbance, transmittance, or percent transmittance

- Apply Gaussian, Lorentzian, or pseudo-Voigt broadening

- Display stick spectra with linear or logarithmic line-strength scaling

- Report the integrated area of the displayed stick spectrum

- Set molecule-specific burdens in ppm·m

- Display the x-axis in wavenumber, cm⁻¹, or wavelength, µm

- Inspect plotted regions with an interactive cursor

- View line-specific cursor information in stick mode, including molecule, isotopologue, line strength, lower-state energy, and HITRAN quantum assignments when available

- Zoom into selected spectral regions by dragging across the plot

- Export calculated spectra as CSV or text files

- Export the displayed plot panel as a JPEG image

- Use Demo Mode to evaluate the app without first downloading a HITRAN file

Applications

- Exploring infrared molecular spectra

- Inspecting HITRAN line positions and line strengths

- Comparing spectral regions for different molecules

- Visualizing gas-phase spectra over selected wavenumber ranges

- Generating simple absorbance, transmittance, or percent-transmittance simulations

- Exporting calculated spectra for external analysis

- Teaching or demonstrating HITRAN line-by-line spectral data