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Homepage of Professor Emeritus Harald Møllendal |
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I am a physical
chemist. I
have been doing research at the University of Oslo since 1965. I have
been teaching chemistry here since 1967. My main experimental technique
is microwave (MW) spectroscopy of gases. This method is characterized
by its extreme accuracy. We have an excellent Stark-modulated
microwave spectrometer operating in the 7 - 120 GHz spectral range. Our
MW studies are normally supported by
quantum chemical calculations. Intramolecular hydrogen bonding (HB) is of great importance in chemistry, physics and biology. Intramolecular HB can best be studied in the gas phase at low pressures where interactions between molecules are minimal, because in condensed phases a change to intermolecular hydrogen bonding often occurs owing to interaction with neighboring molecules. MW spectroscopy is an ideal method of studying intramolecular HB because the experiments are performed in the gas phase at a pressure of a few pascal. We are interested in all kinds of intramolecular HB, but in recent years we have mostly been investigating weak hydrogen bonds where the amino, thiol, phosphino or selenol groups act as proton donors. All molecular properties can in principle be derived from the molecular structure. The determination of the structure is therefore the most fundamental thing a chemist can deal with. Structures determined by MW spectroscopy are the most accurate experimental ones. Quantum chemical calculations can today predict accurate structures of small molecules. A combination of MW data and quantum chemical calculations is often used by us to derive the best possible structure. Rotation about chemical bonds often allows a compound to exist in various geometrical forms called conformers, which generally have different physical properties. The aim of conformational analysis is to describe the properties of these conformers and the barriers to interconversion between them. Conformational analysis is another research field in this laboratory. About 140 different molecules have been detected in interstellar space, largely by their MW spectra. The interstellar space has turned out to have a complicated, almost "exotic", chemistry. It has been speculated that these interstellar molecules played a role in the formation of life on Earth and elsewhere in the universe. The fascinating chemistry of interstellar space and its fundamental implications has triggered my interest in astrochemistry and astrobiology. In this laboratory, MW spectra of molecules of astrochemical interest are being investigated in order to facilitate their identification by radio astronomy. Molecules of biological interest are often selected for study. The reaction paths of interstellar molecules is another interest of mine. These pathways are modeled by quantum chemical calculations. |
Updated March 8, 2013