Collisions between carbon dioxide molecules

Can affect greenhouse warming. Visible light coming from the Sun pours down daily and is reflected back from Earth’s surface as IR radiation. Extra warming occurs when some of that IR is absorbed and retained in the atmosphere. Only a trace gas in the atmosphere, CO₂ is far outnumbered by O₂ and N₂ molecules, but its growing presence (mostly due to human activity) and its ability to absorb and trap IR radiation are thought to be instrumental in producing greenhouse effects. The interactions between atoms in a single molecule generate the molecule’s dipole moment and polarizability, two properties that greatly affect how the molecule absorbs or scatters radiation. Going to the next level of complexity, a new study shows in detail how a large class of molecules, including CO₂, absorbs and sometimes scatters light energy during intermolecular collisions. Michael Chrysos and his colleagues at the...