# First-Principle-Inspired Reduced-Order Models of Chemical-Kinetics in $\\text{H}\_2\\left(\\text{X}^1\\Sigma\_g^+\\right)$+$\\text{H}\\left({}^2\\text{S}\\right)$ System

Source: [First-Principle-Inspired Reduced-Order Models of Chemical-Kinetics in $\\text{H}\_2\\left(\\text{X}^1\\Sigma\_g^+\\right)$+$\\text{H}\\left({}^2\\text{S}\\right)$ System](<https://www.sota2.com/research/paper/697ae9bea2b28e761d87d193>)

Collection index: [llms.txt](<https://www.sota2.com/research/llms.txt>)

Data updated: 2026-01-30T05:00:04.720Z

Authors: Hye Su Jeong, Tae Woong Jeong, Sung Min Jo

Published: 2026-01-28T14:43:28.000Z

## Abstract

In the present study, two-different reduced-order models are proposed for $\\text{H}\_2\\left(\\text{X}^1\\Sigma\_g^+\\right)$+$\\text{H}\\left({}^2\\text{S}\\right)$ system by leveraging first-principle quasi-classical trajectory simulations and in-depth master equation analyses. The most recent available ab-initio potential energy surface is adopted to construct a new set of rovibrational state-to-state kinetic database valid over a wide range of temperatures. Firstly, a modified two-temperature model is proposed by incorporating the master equation-informed model parameters, enabling the advanced treatment of the internal energy coupling and the nonequilibrium dissociation predictions. Secondly, a hybrid coarse-graining model is proposed by combining a graph-based approach optimized globally for a wide range of temperatures with a centrifugal-barrier-based coarse-graining method. The proposed reduced-order models offer significantly improved accuracy in predicting the nonequilibrium energy transfer and dissociation dynamics compared to the existing coarse-graining and 2T models in previous studies. In addition, aerothermal heating prediction relevant to Uranus planetary entry reveals 16.5% of convective heat flux discrepancy compared to the present modified 2T approach with the existing 2T, demonstrating the importance of accurate modeling of the chemical-kinetics in the $\\text{H}\_2\\left(\\text{X}^1\\Sigma\_g^+\\right)$+$\\text{H}\\left({}^2\\text{S}\\right)$ system.

## Recorded benchmark results

A research result applies to its stated dataset, split, metric and evaluation configuration. Compare like-for-like settings, preserve the metric's unit and direction, and distinguish paper-reported results from independent reproduction. The best result recorded here is not a claim of exhaustive, current global coverage.

## Original sources and implementation

[Original paper](<https://arxiv.org/abs/2601.20660>)

[PDF](<https://arxiv.org/pdf/2601.20660.pdf>)