为了研究氮气在宽光谱范围内的色散特性，基于气体色散理论，在标准条件下（温度为293.15 K，气压为101325 Pa），利用二阶Sellmeier公式和最小二乘法拟合得到氮气在0.145～2.058 μm波长范围内的色散公式。该公式在全波段范围内的不确定度约为2.1×10-7，与原始测量数据的准确度一致。与现有色散公式相比，该公式的适用波长范围更宽，可提供氮气在0.27～0.47 μm波段更多的折射率信息，具有较广泛的适用性。通过实验测量氮气在633 nm处的折射率验证了该公式的有效性。

The dispersion formula of nitrogen gas at wavelengths from 0.145 μm to 2.058 μm in standard condition (temperature at 293.15 K, pressure at 101325 Pa) is deduced based on the theory of gas dispersion. A least square method is used for fitting this formula to measured data on the basis of two-order Sellmeier formula. The uncertainty of this formula in the overall spectral range is about 2.1×10-7, which is almost the same as the accuracy of the measured data. Comparing with the current dispersion formulas of nitrogen gas, the new formula presented here covers a wider spectral range, and provides more information of refractive index of nitrogen gas in 0.27～0.47 μm. The validity of the new formula has been approved by measuring the refractive index of nitrogen gas at 633 nm directly.