Sunday, November 3, 2013

Department Seminar

Last Friday at the chemistry seminar a scientist named Brian J. Drouin came to speak about THZ spectroscopy at JPL (terahertz spectroscopy at Jet Propulsion Laboratory California Institute of Technology). He develops new technologies to enhance the measurements of various molecules in the atmosphere and in interstellar space. In space for example carbon dioxide and methane absorb light so the human eye doesn’t see all of the signals. That is, we only see bright lights but much more is going on in the far infrared spectrum; after stars form planets form, and Dr. Drouin ascertains that far infrared spectrums can enable such observations and collection of data. 

There are about 150 identified chemicals in interstellar space, and these technological tools could provide scientists with easier to read data by enhancing the signals on the emission spectra, ultimately aiding in the discovery of more chemicals in space. In earth science the spectrometers being developed can help to analyze with increasing accuracy and in more detail the human effects on stratospheric ozone and the chemical cycles of ozone. Planet Earth is a warm black body that needs to be able to emit heat. Current techniques do not facilitate the viewing of water from up in space, but image FIT (far infrared) can show how much heat is emitted out of Earth, so for example polar regions would be expected to show high levels of heat. This may be a way to measure global warming because less heat emitted from the Earth could be an indicator of an increase in global warming. The instruments can also sense small changes of CO2 globally. 

At present one challenge is to make the spectrometer smaller so it can be more travel friendly. Dr. Drouin talked briefly about his spectrometer, called the frequency multiplication sub millimeter spectrometer that goes from two to 90 wavenumbers, approximately two orders less frequency than IR spectroscopy. He also discussed some things of which I had a hard time following, but overall the presentation was informative.


  1. This is very interesting, I took analytical chemistry and know the basics of chemical spectroscopy, but I never realized that there were spectroscopy methods to analyze interstellar space. It is fascinating that these methods could be used to discover chemicals in space as well as to analyze the earth's ozone layer.

    1. Same here. I'm taking an analytical chemistry this semester and discussed so many chemical spectroscopy, but I never heard any method that can analyze interstellar space. And it's even more fascinating that this is a new technique! I might gather more information of this method. It's very fascinating.

  2. This is an extremely interesting topic, we are so focused on chemicals that surround us on a daily basis that we rarely stop to consider chemical substances abundant in interstellar space. The different absorption of carbon dioxide and methane in space is fascinating to learn about as well, this post described many benefits of (and the need for more research) in spectrometry to continue learning about the world around us and how chemicals react differently in different environments.