《科学大讲堂系列 第241期》Prof. Ralf I. Kaiser：冷化学，热影响：星际空间中的分子复杂性

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  • 题目: 冷化学，热影响：星际空间中的分子复杂性
  • 主讲人：Prof. Ralf I. Kaiser @ 夏威夷大学
  • 时间：2026年5月26日 10:30
  • 地点：理学院一楼化学系C1038报告厅

主讲人简介

Ralf I. Kaiser received his Ph.D. in Chemistry from the University of Münster and Nuclear Research Center Jülich (Germany) in 1994 and conducted postdoctoral work at UC Berkeley (Department of Chemistry). During 1997-2000, he performed his Habilitation at the Department of Physics (University Chemnitz, Germany) and Institute of Atomic and Molecular Sciences (Academia Sinica, Taiwan). He joined the Department of Chemistry at the University of Hawai'i in 2002, where he is currently Professor of Physical Chemistry and Director of the W. M. Keck Research Laboratory in Astrochemistry. His research focusses on Reaction Dynamics & Materials in Extreme Environments spanning Astrochemistry & Astrobiology, Combustion & Energy, Material Sciences, Reaction Dynamics & Kinetics along with Planetary Sciences. These findings have been published so far in 670 peer-refereed publications with an overall H-index of 78 and some 22,000 citations. For his research achievements, Ralf I. Kaiser was elected Fellow of the Royal Astronomical Society (UK), the Royal Society of Chemistry (UK), the Institute of Physics (UK), the American Physical Society (APS), the American Association for the Advancement of Science (AAAS), and of the American Chemical Society (ACS).

讲座简介

Over the past decade, astrochemistry has undergone a paradigm shift: complex organic molecules can form efficiently in the coldest regions of space. Ice-coated interstellar grains are now understood as molecular factories that synthesize biorelevant species within cold molecular clouds and star-forming regions—environments once thought chemically inert. Understanding this reactivity requires bridging gas-phase and condensed-phase chemistry. In this talk, we present molecular beam and surface science experiments that resolve the underlying reaction dynamics and kinetics. In the gas phase, we identify pathways to polycyclic aromatic hydrocarbons (PAHs), key building blocks of carbonaceous nanoparticles. On icy grains, we demonstrate the formation of complex organics—including amino acids, sugars, and polyalcohols—under conditions that challenge conventional assumptions about low-temperature chemistry. Our approach combines isomer-selective vacuum ultraviolet (VUV) photoionization with reflectron time-of-flight mass spectrometry (ReTOF-MS) and infrared (FTIR) spectroscopy, enabled by advanced VUV light sources. These techniques provide molecular-level insight into reaction mechanisms. The results reveal efficient low-temperature routes to aromatic and complex organic molecules via non-classical pathways involving radical–radical reactions, submerged barriers, and excited-state dynamics. Together, these findings redefine how chemical complexity emerges in space and reshape our understanding of molecular evolution in the universe.

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