摘要
TEA CO_2激光将乙烯分子激发到高振动态,振动激发乙烯分子与基电子态钠原子碰撞发生振动—电子(V-E)能量转移,使钠原子处于电子激发态.测定钠原子激发态的荧光,并用所提出的V-E能量转移能级组模型拟合实验数据,获得400℃时乙烯与钠的V-E转移速率常数为2.2×10~5torr^(-1)·sec^(-1).
Ethylene molecules were excited to high vibrational states through multiphoton excitation by TEA CO_2 laser, then collided with Sodium atoms. Energy transfer from vibrational states of ethylene to electronic states of sodium occured.
Measuring the fluorescence from excited electronic states of sodium and fitting these curves to a proposed kinetic model, we can get the rate constant of V(?)E energy transfer for C_2H_4-Na.
Sodium vapor was produced by a heat pipe and adjusted by an input system with three gas pathes. The pulse of fluorescence signal was detected by PMT and observed on the screen of oscilloscope. Typical fluorescence signal can be simply discribed by a biexponential function.
The kinetic mechanism of V-E energy transfer process is following: From the corresponding rate equations we can get that the intensity of fluorescence is proportional to (e ^(?)- e ^(?)). There is a following relation for r_1 and r_2. r_1+r_2=k_(VE)P_(Na)+A+r_d+(k_(EV)+q)P_(C_2)H_4
Since (r_1+r_2) linearly depends on the partial pressure of Na, it is possible to get the slope k_(v(?)) by varying P_(Na).
In this work the temperature was kept at 400℃ and the partial pressures of.P_(Na)were changed between 0.06-0.18 torr. We got the k_(VE)=2.2 ×10~5torr^(-1)sec^(-1).
This result means that the probability of V-E energy transfer per collision is about 1/50. It is rather reasonable.
基金
国家自然科学基金
