UCL LUNCH HOUR LECTURES

Professor Jonathan Tennyson (UCL Physics & Astronomy)

Water vapour dominates the absorption of sunlight by the earth's atmosphere and is the major greenhouse gas. Water is also the third most common molecule in the Universe where it plays an important role in many places from the chemistry of the interstellar medium to the atmospheres of cool stars; detection of water is often taken to be a key first step to detecting life outside our solar system. Given that water is a small and seemingly simple molecule, the way it absorbs and emits light is surprisingly complicated. The lecture will describe some of the issues and how first principles quantum mechanical calculations are now starting to resolve these problems. The results of these calculations are being used for a wide variety of problems including models of the earth's atmosphere and the recent detection of water in an extra-solar planet.