The Calculation of Pressure-Induced Shifts and Pressure- Broadening Coefficients for H20 and Other Important Atmospheric Asymmetric Rotor Molecules

本项目将重点发展一个理论框架，用于计算大气重要物种的压力加宽半宽（）和压力引起的线移（）。半宽是遥感数据和用于计算温室气体辐射强迫的逐行模式的主要误差来源。为了解决这些问题，需要数千个旋转-振动转变的数据。因此，需要一个理论模型，计算效率高，能够达到5%的不确定性。Baranger, Kolb, and Greim （BKG）的可解算子形式论是理论方法的基础。计算将使用实际分子动力学、显式速度平均和相互作用势中的所有相关项。将对大气中重要的转子分子（H2O, O3, SO2, NO2, H2S）进行计算，这些分子被N2或O2和自相互作用扰动。有许多实验测量可以与理论进行比较和检验。一旦这些理论问题得到解决，将为每个物种建立一个重要的大气转换数据库。将研究半宽和线移的振动、旋转状态和温度依赖性。这项工作的主要目标是提高我们对遥感结果的信心，并使我们能够更好地确定温室气体的辐射强迫。

9415454 Gamache This project will focus on the development of a theoretical framework to calculate pressure-broadened halfwidths ( ) and pressure-induced line shifts ( ) for atmospherically important species. The halfwidth is the major source of error in remote sensing data and in line-by-line models used to calculate radiative forcing from greenhouse gases. To address these problems, data are needed for thousands of rotational-vibrational transitions. Hence a theoretical model is needed that is computationally efficient and capable of achieving 5% uncertainty in . The resolvent operator formalism of Baranger, Kolb, and Greim (BKG) is the basis of the theoretical approach. Calculations will use realistic molecular dynamics, explicit velocity averaging, and all relevant terms in the interaction potential. Calculations will be done for atmospherically important rotor molecules (H2O, O3, SO2, NO2, H2S) perturbed by N2 or O2 and self-interactions. There are a number of experimental measurements to compare with and test the theory. Once the theoretical questions are resolved, a database of and for atmospherically important transitions will be generated for each species. The vibrational, rotational state, and temperature dependence of the halfwidths and line-shifts will be investigated. The major objective of this work is to improve our confidence in remote sensing results and allow a better determination of the radiative forcing of greenhouse gases.