报告题目：Exploiting Tunable Vacuum Ultraviolet Light to Unravel the Synthesis of Bio-relevant Molecules in Deep Space
报告人：Prof. Dr. Ralf I. Kaiser
主持人：杨涛研究员
时间：4月13日（周五）上午10:00
地点：理科大楼A814室
主办单位：精密光谱科学与技术国家重点实验室
报告摘要：
Kuiper Belt Objects (KBOs) - small planetary bodies orbiting the Sun beyond Neptune - emerged in their critical role to understand the chemical evolution of the Solar System and how the molecular precursors to life formed and came together to create environments such as on early Earth. This talk presents novel developments in the understanding of the formation of key classes of biorelevant molecules central to the Origins of Life in ices of Kuiper Belt Objects (KBOs) exploring cutting-edge low temperature surface science experiments exploiting soft photo ionization with tunable vacuum ultraviolet light coupled with a time of flight mass spectrometric, isomer selective product detection (PI-ReTOF-MS). By probing for the first time specific structural isomers without their degradation (fragment-free), the incorporation of tunable vacuum ultraviolet photoionization allows for a critical understanding of reaction mechanisms that exist in extraterrestrial ices compared to traditional methods thus eliminating the significant gap between observational and laboratory data that existed for the last decades. Since Rosetta’s lander Philae touched down on 67P/Churyumov–Gerasimenko – a short period comet from the Kuiper Belt - data on the molecular composition of the comet’s surface can be directly compared with the inventory of biorelevant molecules extracted from our experiments thus defining the first inventory of biorelevant molecules, which forms the nucleus for evolution of life in our Solar System billions of years ago. Considering that Kuiper Belts have been observed around stars like Vega outside our Solar System as well, this knowledge can be transferred to extrasolar planetary systems thus revolutionizing our understanding of the origin of cosmic life as we know it and eventually revealing the molecular birthplace of life. Since cometary matter (at least partially) originated from the molecular cloud, which provided the molecular feedstock for our Solar System, these investigations also expose how ubiquitous astrobiologically relevant molecules such as glycolaldehyde, which cannot be formed in the gas phase of the interstellar medium, can be synthesized on ice coated interstellar grains at 10 K via a cosmic-ray initiated non-equilibrium chemistry. With the commission of the Atacama Large Millimeter/Submillimeter Array (ALMA) and the Five-hundred-meter Aperture Spherical Radio Telescope (FAST), the detection of more complex organic molecules in space will continue to grow – including biorelevant molecules connected to the Origins of Life theme - and an understanding of these data will rely on future advances in hard core physical chemistry laboratory experiments ultimately revealing the level of complexity of astrobiologically relevant molecules which can be synthesized in our Universe.
报告人简介：
Prof. Dr. Ralf I. Kaiser is Professor in Department of Chemistry and Director of W. M. Keck Laboratory in Astrochemistry, University of Hawai’i at Manoa. He was elected Fellow of the Royal Astronomical Society (UK, 2005), the Royal Society of Chemistry (UK,2011), the American Physical Society (USA, 2012), the American Association for the Advancement of Science (USA, 2013), the Institute of Physics (UK, 2014), and the American Chemical Society (USA, 2017). With an H-index of 46, he authored in more than 400 publications spanning the areas of Physical Chemistry and Chemical Physics (Reaction Dynamics and Kinetics), Combustion Sciences, Astrophysics, Astrochemistry, Astrobiology and Planetary Sciences. He is particularly interested in exploring the chemical reaction dynamics in extreme environments like in combustion systems and extraterrestrial environments, including but not limited to Titan’s atmosphere, comets, interstellar medium and circumstellar envelopes.