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Vibrational Spectroscopy

Fourier-Transform Infrared Spectrometer (FTIR)
OMNIC Software Basic Instructions


  1. Sign in FTIR use time on RM22 logsheet on Macintosh Computer.
  2. Log in FTIR Computer using your FTIR User ID and Password.
  3. If you use Harrick Seagull or DRIFTS Colletor for reflectance measurement in the main compartment, install it in the main compartment.
  4. Open OMNIC.
  5. Under File, choose Open Options.  Select your last name, and open.
  6. Under File, choose Open Parameters.  Select desired parameters, and open.
    • For the main compartment, your choices are dtgs or mct followed by a number indicating the resolution (dtgs05 means using Detector DTGS with 0.5 cm-1 resolution).
    • For the microscope, choose microref, microtrn, or microatr for the reflected mode,transmitted mode, or ATR mode, respectively.
    • For Attenuated Total Reflection (ATR) with Spectra Tech ProfilIR, choose profiler.
    • For grazing angle specular reflectance mode with Harrick Seagull, choose harrick.
    • For diffuse reflectance measurements with DRIFTS Collector, choose drifts.
  7. If you have chosen one of the mct detectors, add liquid nitrogen to the appropriate detector port.  Remember to install screen B in the main compartment if you conduct transmission measurements using the mct detector.  Otherwise, the saturated ADC may distort spectrum.
  8. Under Collect, choose Collect Setup.  Confirm the parameters.  Change them as needed.  Choose the Background Collection Options that you would like to use.
  9. Under Collect, choose Optical Bench Setup.  Confirm the parameters, and make sure there is adequate throughput.  Sometimes, you may need to click on the Align Bench Button for automatic alignment of the internal mirrors and so for increasing the beam throughput.  The reference peak-to-peak potentials on the interferogram for a simple transmission setup are 10 at gain=2 for DTGS and 10 at gain=1 for MCT with Screen "B" inserted in the beam path.
  10. If you use the main compartment, make sure the proper procedure for purging is followed.  Before inserting your sample on the background, close the baffles using the levers on top of the sample compartment.  Then insert the sample.  After the compartment has been open, the quickest purge is obtained by leaving the baffles closed and leaving the clear Plexiglas window open about a centimeter.  It is generally recommended that you wait two minutes for purging.  Then you may open the baffles and close the clear window.  Of course, the longer you wait, the better the purge.  Also, the best results are obtained when the purge time is the same for the sample and the background.
  11. Save your spectra on your floppy disk.  Or you can store spectra files on our Charfac Storage Computer (CFNTSVR) e:/OPTICAL/FTIRUSER/your path and then connect to the CharFac NT Server Computer from your remote location.  Do not save spectra on Hard Drive C:.
  12. After you are done, reset FTIR beam optics to the Main Compartment by selecting Open Parameters and then choosing dtgs4.prm.
  13. Exit OMINIC software.
  14. Log out of Direct Access by choosing Logout under the Special pull-down menu.
  15. If Harrick Seagull or Drifts Collector was used, remove it from the Main Compartment and store it in its box.  Install the transmission sample holder in the main compartment.
  16. Sign out the FTIR use time on the RM22 logsheet on Macintosh Computer.