Massachusetts Institute Of Technology (MIT), USA
Unambiguously identifying molecules in spectra is of fundamental importance for a variety of scientific and industrial uses; a compelling modern focus is the spectroscopic detection of biosignature gases in exoplanet atmospheres. There are thousands of molecular candidates that could contribute towards a potential biosphere and its associated atmospheric spectrum. Analyses of atmospheres require information about the spectrum of each of its putative components. However, spectral data currently only exist for a few hundred molecules and only of fraction of those have complete spectra (e.g. water, NH3). Consequently, remote detections of molecules are vulnerable to false positives, false negatives and miss-assignments. There is a key need for spectral data for a broad range of molecules. Using a combination of experimental measurements, organic chemistry, and quantum mechanics, ATMOS (Approximate Theoretical MOlecular Spectra) is the program that I will discuss. It:
- Provides approximate spectral data (band centres and relative intensities) for thousands of molecules in seconds.
- Assesses hundreds of molecules simultaneously, highlighting patterns and any distinguishing features. Traditional methods for obtaining spectra are extremely costly and time-consuming (i.e. months/years per molecule); ATMOS will inform prioritisation protocols for future high accuracy studies.
- Demonstrates that, at low resolution, individual spectral features could belong to a large number of molecules. Molecular detections in spectra are often made by assigning one, or a few, spectral features to a given molecule. ATMOS can highlight ambiguities in such molecular detections and also direct observations towards spectral regions that reduce the degeneracy in molecular identification.
2018 October 22, 13:30
Faculdade de CiÍncias da Universidade de Lisboa (C1.4.14)
Campo Grande, 1749-016 Lisboa