Dr. Bishun Khare

December 21, 2006

“Functionalization of  Carbon Nanotubes, a form of Carbon in the Interstellar Medium, and Optical Properties of Tholin Produced in a Methane-rich Early Earth Atmosphere”

NCC 2–1358

This project consists of two areas of interest:

Functionalization of Carbon Nanotubes, a form of Carbon in the Interstellar Medium

Among all the elements, carbon is the most important element involved in organic chemistry including prebiotic chemistry leading to the origin of life. Like all the rest of the elements, its origin is also in stars. Carbon based organic matter on Earth is known to exist in millions of different compounds. However, in the combined interstellar medium and circumstellar region, 88 molecules have been discovered as of July 1991. Most of the detection was made by microwave spectroscopy. Now with growing advancement in sensitivity and resolution of the mid and far infrared spectroscopy combined with the observations by orbiting space telescope, such as Hubble and Space Station, we expect to discover many more molecules in the coming decades.

Optical Properties of Tholin Produced in Methane-rich Early Earth Atmosphere

We propose to conduct laboratory simulation of possible early Earth atmospheres composed of nitrogen, carbon dioxide, and methane. Previous work has indicated that as the methane to carbon dioxide ratio increases to near unity, solid organic material – tholin – is produced. The focus of this proposal is to measure the optical constants in the solar and thermal infrared wavelengths of tholin produced for varying ratios of methane to carbon dioxide. It has been proposed that the photochemically produced haze on the early Earth may have contributed to the greenhouse effect by providing a UV shield for ammonia and methane – both potent greenhouse gases. However, the antigreenhouse effect of the haze may offset the greenhouse cooling. To quantitatively assess this important issue requires knowledge of the optical properties of the haze.