Physicist and Nobel laureate Walter Kohn will make two appearances at Rice University May 1, screening an hour-long documentary about solar energy he helped to complete and delivering a distinguished seminar in theoretical physics. Both events are free.

Kohn, who won the Nobel Prize in Chemistry in 1998 for his role in the development of density functional theory, will screen the documentary film "The Power of the Sun" at 11:30 a.m. in 301 Sewall Hall. The film, which is narrated by famed British comedian John Cleese, was created last year to mark the 100th anniversary of Albert Einstein's paper introducing the concept of light and the 50th anniversary of the invention of the first silicon solar cell at Bell Laboratories. Created for general audiences, the film is described by its producers as "a scientific morality tale: how, starting from the most pure and basic science, through stages of brilliant applied science and engineering, there emerges one of the most promising multi-billion-dollar technologies to help deal with one of the great challenges of our time: energy."

Kohn will present a seminar at 4 p.m. titled in 102 Howard Keck Hall. Kohn, professor emeritus of physics at the University of California-Santa Barbara, will show how concepts from Maxwell's equations can, when appropriately used, provide the means for calculating Van der Waals interaction energies.