INFIA Spectrum Analysis

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INfrared FItting Application

Written by Robert Brotherus (c) 1996,1997, 1998. Current version 2.1

Please note that I have been moved to work in private industry from beginning of year 2000 and am not hence actively developing or supporting Infia any more. The most recent version that can be downloaded from this page is, however, quite stable and hopefully helpful for you. Also source code can be downloaded, and hence extended if need arises. While the code has been compiled with Delphi 4.0, it should be easy to adopt to later Delphi versions.


  • Fully interactive analysis of complicated linear molecule spectras. Symmetric top molecule spectra can be analysed as well, though with limited calculation capabilities.
  • Integration of spectrum observation, assignment and calculation tools into one program - no continous writing of input files or reading output files as necessary with separate programs.
  • Spectrum manipulation including inversion, resampling and baseline reduction.
  • Polynomial peak prediction aiding assignments.
  • Combination difference analysis for band J / lower state assignment.
  • Polynomial molecular parameter fit with lower state fixed or free.
  • Non-linear parameter optimisation for interacting bandsystems with L-resonance, coriolis resonance or anharmonic resonance.
  • Many different views to the data: classical spectrum window with assignment markers, database view of assignments and Loomis-Wood view of peaks and assignments.
  • Quick parameter fitting and peak prediction with strike of a single key.

Spectrum window features

  • Flexible zooming options. Any zoom level selectable.
  • Vertical zooming possible.
  • Interpolation of the spectrum data points for smooth view.
  • Real-time scrolling of the spectrum.
  • Markers displaying peak center positions, peak assignments and predicted wavenumbers.
  • Assignment possible by clicking a peak with mouse.

Loomis Wood display features

  • Plotting of all detected peaks in a band system on a single view.
  • Straightening of the selected band peaks to y = 0 line.
  • Other peak positions plotted vertically relative to the selected band peak positions.
  • No limits on the pixel size of the plot - even sizes like 5000 x 2000 are possible.
  • Full scrolling and zooming capabilities.
  • Color coding of the peaks according to their assignment status.
  • Assignment and deassignments of peaks with mouse clicking - very rapid fitting!
  • Saving of the image to a disk file.

Technical features

  • Fully 32-bit Windows95 program, written with Delphi 4.0. Modular and easily extendable object-based design.
  • Can easily handle spectras with more than 500 000 datapoints, 50 000 peaks and 50 000 peak assignments.
  • Object oriented design for convenient and stable storage of spectrum peaks, assignments, bands, states and molecules.

File attachments


Infia Slideshow


Name Size Creator Creation Date Comment  
ZIP Archive 273 kB Robert Brotherus Mar 25, 2007 20:15    
ZIP Archive 1.48 MB Robert Brotherus Mar 25, 2007 20:15    
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