A Deep Ultraviolet Raman and Fluorescence Spectral Library of 51 Organic Compounds for the SHERLOC Instrument Onboard...

Area of Science:

• Planetary Science
• Astrobiology
• Organic Geochemistry

Background:

• Organic molecules are key biosignatures for extraterrestrial life.
• Spectroscopic instruments like SHERLOC are crucial for in-situ analysis of organic compounds on planetary surfaces.

Purpose of the Study:

• To evaluate the capability of deep ultraviolet (DUV) Raman and fluorescence spectroscopy for detecting, classifying, and identifying organic compounds.
• To assess the performance of the SHERLOC instrument's analog for analyzing diverse organic molecules.

Main Methods:

• Acquired DUV Raman and fluorescence spectra for 51 pure organic compounds using a SHERLOC analog instrument.
• Investigated spectral characteristics of carboxylic acids, polycyclic aromatic hydrocarbons, amino acids, nucleobases, and macromolecular carbon.
• Analyzed spectral data for compound identification and classification.

Main Results:

• DUV fluorescence is detectable for 1- and 2-ring aromatic compounds within SHERLOC's spectral range (250-355 nm).
• Fluorescence spectra alone are insufficient for unambiguous compound identification.
• Raman spectra provide specific structural information, enabling identification of both aromatic and aliphatic compounds within instrumental uncertainty.
• Classification of unknown compounds is possible by comparing Raman peak patterns to established trends.

Conclusions:

• SHERLOC's DUV Raman spectroscopy is a powerful tool for identifying organic compounds in extraterrestrial environments.
• Combining Raman and fluorescence data enhances the capability for organic molecule detection and characterization.
• The study provides a spectral library crucial for interpreting SHERLOC data from Mars and other planetary missions.