‘Exotic Molecules, Ions and Vacuum of Interstellar Space’ to be FORNL topic
Robert N. Compton Sr., Oak Ridge National Laboratory corporate fellow emeritus and University of Tennessee professor emeritus, will speak to Friends of Oak Ridge National Laboratory about “Exotic Molecules, Ions and Vacuum of Interstellar Space” virtually on Zoom at noon Tuesday, Feb. 9.
The interstellar medium (ISM) is the matter and radiation that exists in the vacuum between the stars in our Milky Way galaxy. The ISM consists mainly of hydrogen (90%), helium (9%), and a small component of heavier elements, dust and electrons, stated a news release announcing the meeting.
In 1922, Mary Lee Heger discovered a number of diffuse absorption lines in the radiation from stars reaching the Earth which did not match any known elements or molecules at that time. These spectral features have become known as the diffuse interstellar bands or DIBS. Today about 500 bands have now been identified, in the ultraviolet, visible, and infrared wavelengths. The origin of all of these features has been a mystery until 2015 when the Maier group from Switzerland made a definite assignment of two bands to the Buckminsterfullerene molecular ion C60+.
Sir Harry Kroto had long proposed that some DIBS might be due to interstellar carbon containing molecules and worked with Rick Smalley at Rice University to discover the C60 molecule for which they received the Nobel Prize in 1996.
This subject will be discussed at the meeting, along with a possible new mechanism for the efficient ionization of C60 discovered at ORNL called thermionic emission. Other DIBS have been tentatively assigned to dipole-bound anions. Dipole-bound anions are polar molecules which attach a weakly bound electron to the positive end of the molecular dipole. Dipole-bound anions were first observed at ORNL.
“Included in this talk I will provide a plausible explanation for the observed excess of L-amino acids found in meteors in Australia and Canada. I suggest a process in which circularly polarized microwaves observed in the ISM can convert the D-amino acids into life supporting L-amino acids,” Compton said in the release.
“Finally, we will discuss perhaps the most exotic component of the ISM, the expanding quantum vacuum itself. The Lamb shift and Casimer effect in the vacuum are well described experimentally and theoretically, however, the long-discussed Faraday effect for a vacuum awaits experimental verification. Several false starts in the laboratory illustrates the difficulty of these experiments. However, recently polarized light from a neutron star which has a 1013 Gauss magnetic field is the first observation of the vacuum birefringement. The quantum vacuum will be discussed at a level understandable by an inquisitive pedestrian.”
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This is the latest of the continuing FORNL Technical meetings on Zoom.