Welcome to the Planetary Spectroscopy Research Group and the Vibrational Spectroscopy Laboratory at Stony Brook University, led by Prof. Timothy Glotch. We have a variety of research interests with a focus using vibrational spectroscopy to understand the composition of Mars and the Moon.
Left to right: Gen Ito, Cheng Ye, Mehmet Yesiltas, Katherine Shirley, Congcong Che, Tim Glotch, Steven Jaret, Chip Legett, Jiannan Zhao, Melinda Rucks.
We use a variety of spacecraft and rover data sets to understand the crustal composition of Mars and the Moon. The mineralogy derived from these data sets provides insight into these bodies’ formation and alteration history.
The spectroscopic tools available in the Vibrational Spectroscopy Laboratory allow us to examine geologic materials similar to those that are present on Mars, the Moon, or other solar system bodies. If we can understand the detailed spectral properties of these materials as well as what causes changes in these spectral properties, we can better interpret the remote sensing data.
We use several models to calculate the VNIR and MIR optical constants (n and k) of a variety of minerals of geologic interest. We are also using the publicly available Multiple Sphere T-Maxrix Model to exactly calculate the scattering properties of clusters of spheres of different compositions. Such studies enable the quantitative interpretation of remote sensing data from Earth, Mars, and other bodies.
The Thermo Fisher Nicolet 6700 FTIR spectrometer is modified to collect emissivity spectra in an environment purged of water vapor and CO2. Measurements from 400-4000 cm-1 can be carried out using a KBr beamsplitter and a deuterated L-alanine doped triglycine sulfate (DLaTGS) detector with a KBr window. Measurements from 50-600 cm-1 can be carried out on the same spectrometer equipped with a Solid Substrate beamsplitter and a DTGS detector with a polyethylene window. The spectrometer can be equipped with a SmartOrbit attenuated total reflectance (ATR) accessory with a Type IIa diamond element for ATR analyses or a FT-30 accessory for specular reflectance measurements. The spectrometer can also be equipped with a CaF2 beamsplitter, an InGaAS detector, and a Smart Diffuse Reflectance accessory for diffuse reflectance measurements from 0.8-2.5 μm.
The Nicolet iN10MX FTIR microscope is equipped with a liquid nitrogen-cooled MCT array detector capable of acquiring hyperspectral image cubes between 7000 and 715 cm-1. Pixel sizes are 25 or 6 μm for reflectance and transmission modes and 25 or 1.3 μm for ATR mode. The iN10MX is also equipped with a DTGS detector capable of acquiring 50 x 50 μm or larger point spectra between 4000 and 400 cm-1. The image above is a 2 mm by 2 mm reflectance spectral image of a shocked basalt from Lonar Crater, India. Green pixels are maskelynite, light blue pixels are melt glass, orange pixels are pyroxene, and purple pixels are epoxy.
The WITec alpha300R confocal Raman imaging system is equipped with both 532 nm Nd YAG and 325 nm HeCd excitation lasers. A variety objective lenses provide white light and Raman imaging capability at scales ranging from 260 nm/pixel to several μm/pixel. Hyperspectral Raman images or point spectra can be acquired on mineral or biological samples as well as high pressure materials within diamond anvil cells. Two holographic grating spectrometers allow the collection of Raman spectra at 3 cm-1 or 1 cm-1 spectral resolution over a wide Δcm-1 range. The image to the left is a high-resolution Raman map of a flood basalt sample from Lonar, India, showing the distributions of titanomagnetite, plagioclase feldspar, and pyroxene.