Berlin 2001 – wissenschaftliches Programm

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MO: Molekülphysik

MO 12: Posters Friday: Spectroscopy

MO 12.24: Poster

Freitag, 6. April 2001, 12:30–15:00, AT3

Determination of Interatomic Potentials of the A²Π and B²Σ states of KAr from Laserspectroscopic Data — •M. Braune and D. Zimmermann — Institut für Atomare und Analytische Physik, TU Berlin Hardenbergstraße 36, 10623 Berlin

Over the last years we performed laserspectroscopic absorption experiments on the molecule KAr leading to determination of rovibrational energy levels of several electronic states. After the most recent double resonance experiments in the range of 13048 cm⁻¹ to 13065 cm⁻¹, we determined six vibrational levels v = 6..11 and seven vibrational levels v = 0..6 of the first excited states A²Π and B²Σ, respectively. Using the resulting data of 151 rovibrational levels a quantum mechanical calculation of diabatic and adiabatic interatomic potentials for both states was performed including the numerical Numerov-Cooley algorithm embedded in a least square fit routine. Since there is a strong interaction between the B²Σ and the A²Π_1/2 state due to the spin orbit coupling parameter A(R) the off-diagonal matrix elements of the spin orbit operator were taken into account. In this calculation parameters of analytical functions for the two potentials, such as HFD or a Morse-van der Waals-function, and for the parameter A(R) are varied to minimize the deviation between the experimental data and energy levels calculated with the potential functions. We obtained adiabatic potential curves with an equilibrium distance of R_e = 7.1 Å and a depth of D_e = 26.0 cm⁻¹ for the B²Σ state and R_e = 3.4 Å, D_e = 398.7 cm⁻¹ for the A²Π_1/2 state. As expected, A(R) increases with decreasing internuclear distance, but shows a dent with a minimum at 5 Å.