Berlin 2001 – scientific programme

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PV: Plenarvorträge

PV III

PV III: Plenary Talk

Thursday, April 5, 2001, 09:00–09:45, H105

Spectroscopy of water in the heavens and on earth — •Jonathan Tennyson — Department of Physics & Astronomy, University College London, London WC1E 6BT, UK

Water is the third most common molecule in the Universe and considered fundamental to life. It the major absorber of sunlight in our atmosphere and a significant product of most combustion processes. Its rotation–vibration spectrum has therefore been well studied but remains difficult to analyse because of strong mixing between vibrational modes and because standard perturbation theory techniques are formally divergent for water at low levels of rotational excitation.

Recently we have used first principles calculations which rely on the variational principle to analyse water spectra in sunspots [1], super-heated steam [2], and laboratory spectra extending into the ultra violet [3]. This work represents a paradigm shift in the method used to assign rotation–vibration spectra. The results have important consequences for our understanding of radiative transport through a number of bodies including cold stars and the Earth’s atmosphere [4].

To make further progress on water spectra it has proved necessary to continue development of theoretical models. Our models now include many effects usually neglected in such studies including breakdown of the Born–Oppenheimer approximation and electronic relativistic effects [5]. Recently we have even found that quantum electrodynamic effects may be significant at the 1 cm⁻¹ level [6].

[1] O.L. Polyansky, N.F. Zobov, S. Viti, J. Tennyson, P.F. Bernath and L. Wallace, Science, 277, 346 (1997).

[2] N.F. Zobov, O.L. Polyansky, J. Tennyson, J.A. Lotoski, P. Colarusso, K.-Q. Zhang and P.F. Bernath, J. Mol. Spectrosc., 193, 118 (1999).

[3] N.F. Zobov, D. Belmiloud, O.L. Polyansky, J. Tennyson, S.V. Shirin, M. Carleer, A. Jenouvrier, A.-C. Vandaele, P.F. Bernath, M.F. Marienne and R. Colin, J. Chem. Phys., 113, 1546 (2000).

[4] D. Belmiloud, R. Schermaul, K. Smith, N.F. Zobov, J. Brault, R.C.M. Learner, D.A. Newnham and J. Tennyson, Geophys. Res. Lett., 27, 3703 (2000).

[5] A.G. Csaszar, J.S. Kain, O.L. Polyansky, N.F. Zobov and J. Tennyson, Chem. Phys. Letts., 293, 317 (1998); 312, 613 (1999).

[6] P. Pyykko, K.G. Dyall, A.G. Csaszar, G. Tarczay, O.L. Polyansky and J. Tennyson, Phys. Rev. A., (in press).