Overview of HitranLab

HitranLab provides a macOS desktop interface for working with standard HITRAN-format .par files. The app allows users to load HITRAN line data, select molecules, define wavenumber ranges, apply line-strength thresholds, and generate stick or broadened spectra using common line-shape models.

Key Features of HitranLab:

• Load HITRAN-format .par files

• Select molecules, spectral range, and line strength before loading and plotting spectral data

• Display HITRAN stick spectra directly from HITRAN line strengths. Stick plots may be displayed with either linear or logarithmic line-strength scaling.

• Simulate broadened spectra using Gaussian, Lorentzian, or pseudo-Voigt profiles and display as absorbance or transmittance versus wavenumber

• Adjustable simulation parameters including Gaussian FWHM, Lorentzian FWHM, concentration, path length, and number of plotted simulation points.

• Interactive plotting using the cursor to inspect plotted regions. In stick-spectrum mode, the cursor displays line-specific information, including molecule, isotopologue, line strength, lower-state energy, and HITRAN quantum assignments when available

• Zoom supported by dragging across the plot to zoom into a selected wavenumber region, then reset the view when needed

• Export data as CSV or text files for use in other analysis programs

• Export the displayed plot panel as a JPEG

• Demo mode included to evaluate the app without first downloading a HITRAN file.

A few Applications of HitranLab:

• Exploring infrared molecular spectra

• Inspecting HITRAN line positions and strengths

• Comparing spectral regions for different molecules

• Generating simulated absorbance or transmittance spectra

• Visualizing gas-phase spectra over selected wavenumber ranges

• Exporting calculated spectra for external analysis

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