Laser-Driven Localization of Collective CO Vibrations in Metal-Carbonyl Complexes

TL;DR

This paper demonstrates how two orthogonally polarized IR laser pulses can control the localization of CO vibrational modes in a cobalt dicarbonyl complex, revealing limitations due to anharmonicity.

Contribution

It introduces a laser control scheme for localizing collective vibrational modes in metal-carbonyl complexes and analyzes the effects of anharmonicity on this control.

Findings

Laser pulses can induce localized CO vibrations.

Control is limited by potential anharmonicity.

Wave packet dispersion prevents bond breaking.

Abstract

Using the example of a cobalt dicarbonyl complex it is shown that two perpendicularly polarized IR laser pulses can be used to trigger an excitation of the delocalized CO stretching modes, which corresponds to an alternating localization of the vibration within one CO bond. The switching time for localization in either of the two bonds is determined by the energy gap between the symmetric and asymmetric fundamental transition frequencies. The phase of the oscillation between the two local bond excitations can be tuned by the relative phase of the two pulses. The extend of control of bond localization is limited by the anharmonicity of the potential energy surfaces leading to wave packet dispersion. This prevents such a simple pulse scheme from being used for laser-driven bond breaking in the considered example.