Chaos Gated Tunneling Drives Molecular Reactivity in Astrophysical Environments
Saptarshi G. Dastider, K. Prashant, P. Shruti, C. Sudheesh, Jobin Cyriac
TLDR
A new chaos-diagnostic framework reveals how suppressed chaos at transition states enhances quantum tunneling, driving molecular reactivity in ultracold astrochemical environments.
Key contributions
- Introduces a chaos-diagnostic framework combining electronic structure, AGP, and RMT for ion-molecule reactions.
- Demonstrates that suppressed quantum chaos at transition states enhances tunneling probabilities in ultracold environments.
- Proposes a "fragility index" using AGP slope to quantify how vibrational modes reintroduce chaos and suppress reactivity.
- Provides a generalizable metric to identify vibrationally gated pathways in complex astrochemical networks.
Why it matters
This paper offers a novel theoretical framework to accurately model complex ion-molecule reactions in ultracold astrophysical environments. By identifying how quantum chaos influences tunneling, it provides crucial insights for refining kinetic models of planetary and interstellar plasmas. This improves our understanding of chemical evolution in giant planet atmospheres.
Original Abstract
Accurate modeling of ion-molecule reaction networks is essential for understanding the chemical evolution of planetary ionospheres, particularly for giant planets where proton-transfer chains drive atmospheric composition. However, predicting reaction rates in these ultracold environments remains a challenge due to the non-trivial interplay between vibrational dynamics and quantum tunneling. In this work we present a chaos-diagnostic framework that integrates multireference electronic structure theory, Adiabatic Gauge Potentials (AGP), and Random Matrix Theory (RMT) to characterize the microscopic dynamics of proton transport. Using the formation of H+3 and the proton-bound cluster H+5 as representative model systems relevant to Jovian atmospheres, we demonstrate that the transition state acts as a dynamical bottleneck where quantum chaos is notably suppressed, effectively enhancing tunneling probabilities. We introduce a fragility index based on the AGP slope to quantify how specific vibrational modes reintroduce chaos and suppress reactivity. This diagnostic approach offers a generalizable, data-driven metric for identifying vibrationally gated pathways in complex astrochemical networks, providing a theoretical basis for refining kinetic models of planetary and interstellar plasmas
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