可见光谱区水汽分子碰撞加宽的理论计算

CALCULATION OF COLLISION BROADENING OF WATER VAPOR ABSORPTION LINES IN THE VISIBLE REGION

根据能级的实验数据,采用最小二乘法拟合得到水汽分子(202),(122)和(004)振动态的Watson的Hamiltonian常数值。利用这些常数值和修正的量子傅里叶变换(QFT)(即QFT~*)方法,分别计算了水汽分子(202)带中已有实验数据的一些谱线的氮分子碰撞加宽线宽,以及(202),(122)和(004)带~eR(1,1)支谱线的氮分子碰撞加宽线宽、及线宽的温度依赖关系。与实验结果比较表明,利用拟合方法求得的Hamiltonian常数值是合理的,而且QFT~*方法也可应用于计算水汽分子可见光谱区的碰撞加宽线宽。计算结果还表明,在水汽分子可见光谱区,不仅碰撞加宽线宽、而且线宽的温度依赖指数都随振动量子数和转动量子数的变化而变化,其最大变化范围均可高达一倍以上。

The least-squares fitting of the observed energy levels to the Watson' s Hamiltonian con-stants of water vapor vibrational states (202), (122), and (004) had been performed. Using these constants and the revised quantum Fourier transformation (namely QFT*) method, we calculated the N2-broadened widths of the observed absorption lines for (202) band. Also we obtained the N2-broadening widths and temperature dependences of lines in the R(l ,1) branch of (202), (122), and (004) bands. The agreement between calculation and experiment show that the fitting to the Hamiltonian constants is reasonable and the QFT* method can be ap-plied to calculate the collision broadening of water voapor in the visible region. In addition, the calculated results indicated that in the visible region the collision broadening and line-width temperature dependence vary with the rotational and vibrational quantum numbers, and the maximum values of these two parameters might be two times as large as the corresponding minmum value.