Abstract In our previous work, four environment parameters including temperature, pressure, relative humidity and carbon dioxide concentration in a long gauge block interferometer chamber were measured continuously for 24 h. The refractive index of air in the chamber depending on three measured parameters was determined using the updated Edlén equation by assuming that CO2 concentration is constant at 450 ppm. In this study, the carbon dioxide concentration term was added into the updated Edlén equation and four environment parameters including temperature, pressure, relative humidity and CO2 concentration were measured continuously for 12 h. To characterize the influence of the carbon dioxide concentration on the refractive index of air in a long gauge block interferometer chamber, the refractive index of the chamber contents was determined using updated Edlén equations with constant and with variable carbon dioxide concentration terms. The results showed that the refractive index values obtained from the updated Edlén equations with constant and variable CO2 concentration terms were equal to 1.000268244 and 1.000268261, respectively.

中文翻译：

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二氧化碳浓度对长量块干涉仪中空气折射率的影响

摘要 在我们之前的工作中，连续测量了长量块干涉仪室内的温度、压力、相对湿度和二氧化碳浓度四个环境参数，持续 24 小时。通过假设 CO2 浓度恒定在 450 ppm，使用更新的 Edlén 方程确定腔室中空气的折射率取决于三个测量参数。在这项研究中，二氧化碳浓度项被添加到更新的 Edlén 方程中，并连续测量了四个环境参数，包括温度、压力、相对湿度和 CO2 浓度，持续 12 小时。为了表征二氧化碳浓度对长量块干涉仪室中空气折射率的影响，使用更新的 Edlén 方程确定腔室内容物的折射率，该方程具有恒定和可变二氧化碳浓度项。结果表明，从具有恒定和可变 CO2 浓度项的更新 Edlén 方程获得的折射率值分别等于 1.000268244 和 1.000268261。