Line Shape for Collision Systems Important in Earth's, Planetary, and Exoplanet Atmospheres

被大气中的水和微量气体吸收的红外线和太阳辐射驱动着大气化学和气候。单个物种以独特的光谱带和窗口吸收辐射，每个分子的吸收量随压力和温度的变化而变化。为了准确地计算大气吸收的能量并利用遥感技术对这些分子进行探测，需要精确的逐线光谱吸收参数及其随环境参数的变化。本研究利用基础物理学的方法构建了关键大气物质的精确线形参数，这些参数将用于大气辐射和遥感反演模型，以提高我们对大气化学的认识。这项研究将建立一个统一的理论框架来计算压力加宽的半宽度和压力引起的线移，以及它们对地球大气中重要气体的速度和温度的依赖。改进后的形式将超越目前的Voigt剖面近似值，以增强遥感检索和逐行计算气候辐射强迫。该研究将开发新的Hartmann-Tran剖面，该剖面需要依赖于速度的线形参数，这些参数将从数千个反振动跃迁中估计出来，这些跃迁将使用从头算和修正复Robert-Bonamy代码进行计算。它的目标是H2O、CO2、O3和CH4在与大气相关的温度和压力下与N2、O2碰撞和自碰撞时的谱线展宽。具体来说，线耦合和混合对半宽度的影响将使用现有的观测数据进行严格的处理和校准。除了推进美国社区的HITRAN数据库外，重点研究还将丰富遥感检索和微量气体的辐射强迫，以推进大气化学和气候。

Infrared and solar radiation absorbed by atmospheric water and trace gases drives atmospheric chemistry and climate. Individual species absorb radiation in unique spectral bands and windows and the amounts vary with pressure and temperature for each molecule. In order to accurately compute the energy absorbed by our atmosphere and to use remote sensing to detect these molecules accurate line by line spectral absorption parameters including their variation with environmental parameters is needed. This research uses fundamental physics to construct accurate line shape parameters of key atmospheric species that will be used in atmospheric radiation and remote sensing retrieval models to advance our knowledge of atmospheric chemistry.This research will develop a unified theoretical framework to calculate pressure-broadened half-widths and pressure-induced line shifts, their velocity and temperature dependences for gases important in the Earth's atmosphere. The improved formalism will go beyond the current Voigt profile approximation to enhance remote sensing retrievals and line-by-line computations of radiative forcing of climate. The research will develop the new Hartmann-Tran profiles that require velocity dependent line shape parameters that will be estimated from thousands of ro-vibronic transitions that will be computed using ab initio and Modified Complex Robert-Bonamy codes. It will target H2O, CO2, O3 and CH4 line broadening in collision with N2, O2, and self-collisions at atmospherically relevant temperatures and pressures. Specifically, the effects of line coupling and mixing on half-widths will be rigorously treated and calibrated using available observations. In addition to advancing the U.S. community HITRAN database focused studies will enrich remote sensing retrievals and radiative forcing by trace gases to advance atmospheric chemistry and climate.