A comprehensive semi-classical study of the collisional line broadening and shift coefficients of C2H2 by several key perturbers (H2, He, N2, C2H2, CO, and CO2) for astronomical applications using the Complex Robert–Bonamy–Ma (CRBM) framework is presented. Following the CRBM computational protocol, the intermolecular interaction potentials are constructed from atom–atom and electrostatic interactions, and then fitted to reproduce experimental room-temperature line-broadening parameters taken from the literature. In total, 657 experimental values are used in the fitting. The empirical potentials are then used to predict line broadening coefficients over a wide temperature range. Reference collisional line widths γ0 and temperature exponents n for the commonly used single-power law are produced, as well as a set of parameters for the double-power law, which better reproduces the temperature dependence of theoretical predictions. The vibrational dependence of the line widths is studied using a new ab initio isotropic polarizability surface of C2H2 and is found to be negligible. The computed line broadening parameters are found to agree well with the experimental data, while the modelling of line shifts of HCCH is not satisfactory when compared to the experiment. The new line broadening data of C2H2 with the J (or m) dependence have been used to populate the ExoMol database www.exomol.com as part of the ExoMol pressure-broadening diet and can be used to model opacities of atmosphere of (extrasolar) planets. The CRBM methodology tested here on C2H2 can be used for other similar (closed-shell) systems in ExoMol that are important for exoplanetary atmospheric studies.

中文翻译：

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使用复 Robert-Bonamy-马 方法计算乙炔的碰撞线展宽和偏移


本文使用复杂的罗伯特-博纳米-马 （CRBM） 框架，对几个关键扰动因子（H2、He、N2、C2H2、CO 和 CO2）对 C2H2 的碰撞线展宽和移位系数进行了全面的半经典研究。按照 CRBM 计算协议，分子间相互作用势由原子-原子和静电相互作用构建，然后拟合以重现文献中获取的实验室温线展宽参数。拟合中总共使用了 657 个实验值。然后，使用经验电位来预测较宽温度范围内的线展宽系数。生成了常用的单幂定律的参考碰撞线宽 γ0 和温度指数 n，以及双幂定律的一组参数，更好地再现了理论预测的温度依赖性。使用 C2H2 的新从头各向同性极化表面研究了线宽的振动依赖性，发现可以忽略不计。发现计算的线展宽参数与实验数据吻合良好，而与实验相比，HCCH 的线偏移建模并不令人满意。具有 J（或 m）依赖性的 C2H2 的新线展宽数据已被用于填充 ExoMol 数据库 www.exomol.com 作为 ExoMol 压力展宽饮食的一部分，可用于模拟（太阳系外）行星大气的不透明度。这里在 C2H2 上测试的 CRBM 方法可用于 ExoMol 中其他对系外行星大气研究很重要的类似（闭壳）系统。