对称陀螺分子高温光谱的理论研究

The molecular spectra at normal temperature have been extensively studied. However, there are few contributions devote to the high-temperature spectra, especially for the high temperature of 5000 K. Up to now, a plenty of spectral experiment measurements and theoretical calculations still focus on normal and mid-high temperature. In HITRAN database, we can only obtain the line intensities at the temperature up to 3000 K by extrapolating method..In this study, the high temperature spectra of symmetric-top molecule NH3、PH3、HNO3、HCO3、CH3 are investigated and the line intensities of NH3、PH3、HNO3、HCO3、CH3 are obtained at several high temperature. The calculation of rovibrational energies in the electronic ground state of NH3, PH3, HNO3, HCO3, CH3 is based on high level ab initio potential surfaces and on the Hougen-Bunker-Johns(HBJ) approach. The partition functions are directly calculated. The theoretical calculation formulae are further analysed and modified by comparing with the values obtained from experiments. We will calculate the partition functions and line intensities of symmetric-top molecule NH3、PH3、HNO3、HCO3、CH3 at the higher temperature 4000 and 5000 K. Meanwhile, we also present the simulated spectra of mentioned molecules at the same high temperature. The results are of significance for the studying of the molecular spectra at high temperature including experimental measurements and theoretical calculation.

对称陀螺分子是陆地大气和非陆地行星大气中广泛存在的一类重要分子，其高温辐射特性在航空航天领域有重要应用背景。目前国际上尚未见高于3000K的高温光谱数据的报道。本项目拟对NH3、PH3、HNO3、HCO3、CH3等对称陀螺分子的高温振转光谱进行理论研究，通过高精度从头算和基于HBJ方法的变分模型计算得到分子电子基态下的振转能级；并直接计算分子配分函数，探索对称陀螺分子高温光谱的理论计算方法。通过对3000K以下的计算值与实验值及HITRAN数据的比较，分析修正高温光谱理论计算方法，最终获得分子在高达6000K极端高温下的振转模拟光谱，为高温光谱的实验和理论研究提供一定的参考数据，为气动物理的高超声速技术研究提供实用数据，丰富原子分子光谱理论。

对称陀螺分子是陆地大气和非陆地行星大气中的一类重要分子，其高温辐射特性在航空航天领域有重要应用背景。本项目采用乘积近似法计算了对称陀螺分子NH3、PH3、HNO3等在10-6000K温度范围的分子配分函数，其中转动配分函数用McDowell的非刚性转子模型，考虑了高温修正，包括四阶和六阶离心扭曲修正，振动配分函数用谐振子模型。在直接计算分子配分函数的基础上，将无转动跃迁偶极矩平方近似为一常数，利用分子光谱的振转强度理论获得对称陀螺分子高温光谱的理论计算方法，计算获得NH3、PH3、HNO3等对称陀螺分子在不同温度下的跃迁谱线强度，计算获得的谱线强度在常温和3000K的高温均与实验值及HITRAN数据库的结果符合很好。项目进一步计算获得上述分子在高达4000-6000K极端高温下的振转模拟光谱。研究结果在航空航天技术等领域有重要应用背景，特别是对研究高超声速飞行器再入大气层时的气动物理有重要意义。本项目较好地完成了预期研究任务，特别是培养了一批中青年教师，在贵州省形成了原子与分子物理科研团队。