Berlin 2001 – scientific programme

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MO: Molekülphysik

MO 7: Posters Wednesday: Theory: Structure and Dynamics

MO 7.2: Poster

Wednesday, April 4, 2001, 12:30–15:00, AT3

High accuracy ab initio analysis of the spectrum of water — •Paolo Barletta¹, Jonathan Tennyson¹, Oleg Polyansky¹, and Attila Császár ² — ¹Department of Physics and Astronomy UCL — ²Department of Theoretical Chemistry, Eötvös University ,H-1518 Budapest 112

Recently Császár et al. showed that one-particle relativistic corrections to the PES are significant for a better understanding of its spectrum[1]. We have proceeded further, including two particle relativistic corrections to the electronic interaction in our PES. This correction, namely the Breit term, is supposed to give a contribution to the PES of the same order of magnitude than the one-particle relativistic corrections added by Császár  i.e., we are dealing with term of order (α Z)². In fact, the Breit term is found to contribute up to 5 cm⁻¹ to the vibrational band origins [2]. To compute the Breit corrections to our PES we used the progran BERTHA of Quiney et al. [3], while to obtain the energy levels we used the code DVR3D.

We will also discuss simple models which allow for the BO non-adiabatic corrections. References

[1] A. Császár , J.S. Kain, O.L. Polyansky, N.F. Zobov, and J. Tennyson. Chem. Phys. Letters, 293 (1998) 317

[2] H.M. Quiney, P. Barletta, g. Tarczay, A. Csaszar, O.L. Polyansky, and J. Tennyson. Chem. Phys. Letters, to be submitted (2001)

[3] H.M. Quiney, M. Skaam, and I.P. Grant. Adv. q. Chem., 32 (1998) 1.