Decomposition of the electronic decoherence induced by the nuclear motion into contributions of individual modes

Ultrafast dynamics of the electron density of a molecule can be initiated by the creation of a superposition of electronic states [1]. The strong correlation between the nuclear and electronic motion typically induces a fast decoherence within just a few femtoseconds, making the experimental observation of electronic oscillations challenging [2]. We recently developed an efficient method [3, 4], based on the semiclassical description of the nuclear motion after a molecular ionization [5], to find molecules with long-lasting electronic coherence and charge migration. We found that the hole oscillations in the but-3-ynal molecule after ionization out of the HOMO lasts for about 10 femtoseconds. Here we show that extending the carbon skeleton to obtain the pent-4-ynal molecule conserves the ionization spectrum and long-lasting charge migration. The semiclassical description of the nuclear motion allows to decompose the overall decoherence into individual normal mode contributions without additional computation. In agreement with the observation made in [6], we find that in molecules with planar symmetry, only the in-plane normal modes contribute to the decoherence.

[1] Cederbaum, L. S.; Zobeley, J. Chemical Physics Letters 1999, 307 (3), 205–210.

[2] Vacher, M.; Mendive-Tapia, D.; Bearpark, M. J.; Robb, M. A. J. Chem. Phys. 2015, 142 (9), 094105.

[3] Scheidegger, A.; Vanícek, J.; Golubev, N. V. J. Chem. Phys. 2022, 156 (3), 034104.

[4] Scheidegger, A.; Golubev, N. V; Vanícek, J. CHIMIA. (Under review).

[5] Golubev, N. V.; Begušic, T.; Vanícek, J. Phys. Rev. Lett. 2020, 125 (8), 083001.

[6] Vester, J.; Despré, V.; Kuleff, A. I. arXiv November 28, 2022.