Where to free protons originate ?
In the temperature range 340–426°C its vapor pressure " p " can be described with the Antoine equation formula_1 where " T " is temperature , " A " = 4.16272 , " B " = 1371.358 K and " C " = -58.496 K. The optical absorption spectrum of pyridine in hexane contains three bands at the wavelengths of 195 nm ( π → π*transition , molar absorptivity ε = 7500 L· ( mol·cm ) −1 ) , 251 nm ( π → π*transition , ε = 2000 L· ( mol·cm ) −1 ) and 270 nm ( n → π*transition , ε = 450 L· ( mol·cm ) −1 ) .