signature=91a105cb2cb53791d3b3de09f3c8d394,[formula omitted] Jahn–Teller effect in the [formula omit...

摘要：

The Jahn–Teller effect in the electronic ground state of theP4+radical cation, which is one of the strongestE×eJahn–Teller effects known in nature, has been revisited in this work with computational methods. The relevance of the Jahn–Teller coupling terms beyond second order in normal-mode displacements has been investigated. An elegant and efficient scheme based on polynomial invariant theory has been employed to expand theE×epotential energy matrix up to arbitrarily high orders in normal mode displacements. Using the state-averaged complete-active-space self-consistent-field method and a correlation consistent double-ζbasis set, an accurateab initioadiabaticE×eJahn–Teller potential-energy surface was obtained. It is shown that a polynomial expansion of least up to sixth order is necessary to account for the pronounced anharmonicity of theab initiopotential-energy surface for large amplitude displacements of the Jahn–Teller active vibrational mode. The vibronic structure of theX̃2Eband of the photoelectron spectrum of P4has been computed using a time-dependent wave-packet propagation method. The results reveal the significance of the higher-order Jahn–Teller coupling terms for the high-resolution vibronic spectrum as well as for the low-resolution band shape.

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