title: Remote Raman Efficiencies and Cross-Sections of Organic and Inorganic Chemicals.
abstract: We determined Raman cross-sections of various organic liquids and inorganic polyatomic ions in aqueous solutions with a 532 nm pulsed laser using remote Raman systems developed at the University of Hawaii. Using a calibrated integrating sphere as a light source, we converted the intensity counts in the spectrum of the light from the integrating sphere measured with UH remote Raman instrument to spectral radiance. From these data, a response function of the remote Raman instrument was obtained. With the intensity-calibrated instrument, we collected remote Raman data from a standard 1 mm path length fused silica spectrophotometer cell filled with cyclohexane. The measured value of the differential Raman cross-section for the 801 cm-1vibrational mode of cyclohexane is 4.55 × 10-30cm2sr-1molecule-1when excited by a 532 nm laser, in good agreement with the values reported in the literature. Using the measured cyclohexane Raman cross-section as a reference and relative Raman mode intensities of the various ions and organic liquids, we calculated the Raman cross-sections of the strongest Raman lines of nitrate, sulfate, carbonate, phosphate ions, and organic liquids by maintaining same experimental conditions for remote Raman detection. These relative Raman cross-section values will be useful for estimating detection capabilities of remote Raman systems for planetary exploration.
authors.affiliation: Hawai'i Institute of Geophysics and Planetology, SOEST, University of Hawaii at Manoa, Honolulu, Hawai'i, USA.
authors.forename: Tayro E
authors.initials: TE
authors.lastname: Acosta-Maeda
authors.affiliation: Hawai'i Institute of Geophysics and Planetology, SOEST, University of Hawaii at Manoa, Honolulu, Hawai'i, USA.
authors.forename: Anupam K
authors.initials: AK
authors.lastname: Misra
authors.affiliation: Hawai'i Institute of Geophysics and Planetology, SOEST, University of Hawaii at Manoa, Honolulu, Hawai'i, USA.
authors.forename: John N
authors.initials: JN
authors.lastname: Porter
authors.affiliation: Hawai'i Institute of Geophysics and Planetology, SOEST, University of Hawaii at Manoa, Honolulu, Hawai'i, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: Bates
authors.affiliation: Hawai'i Institute of Geophysics and Planetology, SOEST, University of Hawaii at Manoa, Honolulu, Hawai'i, USA.
authors.forename: Shiv K
authors.initials: SK
authors.lastname: Sharma
keywords: Raman cross-section; Raman spectroscopy; planetary science instruments; remote Raman; remote sensing; standoff Raman