Upgraded spectrometer able to analyse outer space
18 May 2016 by qmtbqdmdjq.d qmtbqdmdjq.d
A spectrometer has had its capabilities extended to identify large, complex molecular structures found in explosives, fuels, and gases around stars.
A spectrometer has had its capabilities extended to identify large, complex molecular structures found in explosives, fuels, and gases around stars.This has been made possible due to a cooling method developed by Harvard University scientists. They will use a laser ‘combing’ technique, which has been used to detect diseases from breath analysis and contaminants in semiconductors.
Molecules to be analysed are placed in a hollow cavity, with a laser that reflects inside it. A small fraction of this light is absorbed at specific frequencies at which the molecules are rotating and vibrating, creating a unique ‘fingerprint’ of the molecules. Previously, this method was limited to analysing small, simple molecules composed of less than 10 atoms.Jun Ye, JILA/National Institute of Standards and Technology (NIST) fellow, said: “Being able to detect and unambiguously identify large molecules has been a longstanding goal. First, it provides fundamental insights into molecular structure and dynamics. Second, it allows us to understand increasingly complex systems. Third, for applications ranging from breath analysis to explosives detection, the capability to detect large molecules has been missing.”
Previously the molecules were analysed at room temperature. The improved system uses Harvard’s helium buffer gas cooling method, reducing the temperature to minus 265°C – near absolute zero. This greatly slows the molecules’ speed and rotation. The lower temperature also simplifies and strengthens absorption signals and allows the molecules to be measured for more than 10 milliseconds. Ye said it was like “being able to see individual trees instead of just a glob of mountains in the signals.”
High-resolution absorption patterns of carbon-hydrogen bonds were seen in a variety of molecules. They included nitromethane, used in pharmaceuticals, napthelene, detected in interstellar space and hexamethylenetetramine, also of interest in astronomy and pharmaceuticals.
The research was published in Nature.
