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The ON2.3 laboratory:
Fax:   +48-22-
Phone: +48-22-


at the Institute of Physics, Polish Academy of Sciences

For historical reasons this laboratory is called  ON2.3 - Millimetre and Submillimetre Spectroscopy

We have, however, exceeded our original brief and are currently involved in research in rotational spectroscopy at frequencies from 2 to ca 500 GHz.

Staff and PhD students

Doc. dr hab. Zbigniew KISIEL
Mgr Oleksandr DESYATNYK



       Our research is mainly concerned with recording and analysis of pure rotational spectra of molecules and of weakly bound intermolecular complexes.  These studies are carried out in the gas-phase and the spectra arise from quantised end-over-end rotation of molecules.  Their analysis allows highly precise determination of the geometry, of the electric dipole moment, and of inter- and intra-molecular interactions in the studied species.  An important feature of the derived molecular information is that it is for isolated molecules and has traditionally provided a benchmark for ab initio quantum chemistry calculations.

       There are two principal lines of our research:


  Rotational spectroscopy of small molecules, including species of atmospheric interest:
         Recent studies include those of:      
  CBrClF2 (halon BCF)   CHF2Cl (freon-22)   CH2Cl2
  CH2I2   H2C=CCl2   Cl2C=CHCl
  H2C=CClCN   Cl3CCH3   tBuX, X = F...I, CN, NC
  pyrimidine   1-F-adamantane  

       Their aim has been to determine new molecular information as well as spectroscopic constants for use in environmental (i.e. atmospheric and astrophysical) monitoring.


  Rotational spectroscopy of intermolecular complexes:
         Recent examples:
  H2O...HCl   (H2O)2HCl   (H2O...HCl)...Ar
  36Ar...HCl   Ar2...HBr   ArnHX, n=2,3, X=F...Br
  N2...HCl   N2...HBr   Pyrimidine...H2O

       Those studies were devoted to determination of the geometry, dipole moment, nuclear quadrupole splitting constants, and of the effect of the shape of the intermolecular potential on the measured spectroscopic observables.



       Most of our experimental studies are performed on equipment constructed in our laboratory, which currently consists of two complementary spectrometers:


  A broadband millimetre wave (MMW) spectrometer:



       The spectrometer is based on Istok-type high-frequency Backward Wave Oscillators. The sources are phase locked, in two PLL loops, to a 3 GHz synthesiser. Measurements are made in transmission using source modulation, second derivative detection, and GaAs or InSb detectors. The preferred operating range is 150-350 GHz, although the available coverage is from <100 to >500 GHz. The picture shows the free-space optics of the higher frequency PLL loop, which locks the source to a K-band harmonic.


  A cavity Fourier Transform Microwave (FTMW) spectrometer
       This spectrometer allows recording of sub-Doppler spectra of supersonically cooled samples.  The operating range is 2-18.5 GHz and electrodes for Stark measurements are available.  It is possible to measure spectra in standard supersonic expansion through a standard circular pulsed nozzle, with a heated nozzle, and with a nozzle equipped with electric discharge. The white high-vacuum cavity contains a confocal Fabry-Perot microwave resonator with 50 cm diameter mirrors.


  Programs for ROtational SPEctroscopy

       The processing and interpretation of spectroscopic data is often a computationally intensive task and the availability of suitable programs is crucial to the efficiency of such studies.  For this reason we maintain a database of computer programs dealing with various aspects of the rotational spectroscopy problem. The PROSPE database contains extensively tested, well documented programs written both in this laboratory and elsewhere.



  Some recent studies and publications

Weakly bound intermolecular complexes:

Trichloroethylene, Cl2C=CHCl (a well known solvent):

1,1,1-trichloroethane, Cl3CCH3 (another popular industrial solvent):

Chlorobromodifluoromethane, CBrClF2 (the popular fillant for fire extinguishers, removed from use following concerns over the well-being of the ozone layer):

Chlorofluoromethane, CHF2Cl (the freon CFC-22, widely used as an intermediate replacement for the CFC-11 and CFC-12 refrigerants which were relegated from use due to adverse effect on the ozone layer):

Methylene iodide, CH2I2 (a rather taxing problem for rotational spectroscopy):

Some other molecules recently studied with either the MMW or FTMW spectrometers in Warsaw (or both):


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