May 10, 2024
The humble snowflake presents a remarkably difficult challenge for scientific analysis, as the seemingly simple process of water vapor freezing into ice yields a rich menagerie of self-assembling morphologies depending on environmental conditions. Physically realistic computational growth models are beginning to show promise, but they cannot yet reproduce even basic laboratory experiments. In large part, this unfortunate situation exists because the ice crystal exhibits a complex solid/vapor interface exhibiting surface premelting and highly anisotropic molecular attachment kinetics. I will describe the phenomenology of snow crystal growth provided by laboratory measurements along with a new physical model that may finally provide a comprehensive picture of the underlying molecular processes.
Kenneth Libbrecht was educated at Caltech and Princeton, earning his PhD in physics in 1984. He then joined the faculty at Caltech, where his activities included research in helioseismology, laser cooling and trapping of neutral atoms, diode laser technology, and the search for gravitational radiation from astrophysical sources. In the mid-1990s, Libbrecht's interest in the molecular dynamics of crystal growth led him to a detailed study of how ice crystals grow from water vapor, which is essentially the physics of snowflakes. This ongoing endeavor seeks to better understand how crystals grow and how complex patterns emerge in the process. He has authored several books on this topic, including The Snowflake: Winter’s Frozen Artistry, Ken Libbrecht’s Field Guide to Snowflakes, and the recent physics monograph Snow Crystals: A Case Study in Spontaneous Structure Formation.