基于热效应修正和指数函数拟合的光电效应法测量普朗克常数

光电效应法测量普朗克常数的理论依据是爱因斯坦光电方程,但该方程在绝对零度条件下才成立,而实验一般是在室温下进行。温度的影响必然会使计算结果存在一定的误差,为了减小这一误差,以金属阴极的光电效应为例,对普朗克常数测量原理进行热效应修正,引入了准爱因斯坦光电方程。理论推导得出一定温度下阴极光电流与反向电压呈指数函数关系,并在数据处理时采用指数函数拟合光电流-电压实验数据,再通过拐点法确定截止电压。计算结果表明,传统光电效应法的测量误差为14%,热效应修正后的测量误差为1.8%。

Calculating the Planck Constant by Modified Photoelectric Effect considering thermal effect and exponential function fitting

Calculating the Planck constant is based on Einstein photoelectric equation which is valid at absolute zero of temperature. Generally, we carry out experiments at room temperature and calculation error caused by temperature occurs. In order to reduce the error, Einstein photoelectric equation has been modified considering the effect of temperature and quasi-Einstein photoelectric equation is introduced of cathode. Theoretical deduction shows that the relationship between the cathode photocurrent and reverse voltage is exponential function at a certain temperature. The relationship is fitted with an exponential function and then inflection point technique is used to acquire the cut-off voltage. The result shows that the traditional error is 14% and the corrected error is 1.8%.