Here 𝑛𝑛 represents a temperature dependent parameter, 𝑛𝑛 𝑟𝑟𝑒𝑒𝑟𝑟 is its value at reference temperature namely 𝑇𝑇 𝑟𝑟𝑒𝑒𝑟𝑟 , 𝐸𝐸 𝑛𝑛 𝑡𝑡𝑐𝑐𝑡𝑡 is the activation energy, 𝑅𝑅 is the gas constant, and 𝑇𝑇 is the temperature in Kelvin. The activation energy can be evaluated by finding the slope 𝑐𝑐 of plot ln (𝑛𝑛) vs. 1/𝑇𝑇: