The photoionization of N2 in the thermosphere absorbs much of the high-energy radiation coming from the sun. If the ionization e
nergy of N2 is 1495 kJ/mol, what is the maximum wavelength of a photon that would have sufficient energy to ionize N2? To which region of the electromagnetic spectrum does this photon belong?
1 mol of photons required for the photoionization of N₂ has an energy (E) of 1495 kJ = 1495 × 10³ J = 1.495 × 10⁶ J. We can find the wavelength (λ) associated with this energy using the Planck-Einstein equation.
E = h . c . λ⁻¹
where,
h is the Planck's constant
c is the speed of light
E = h . c . λ⁻¹
λ = h . c . E⁻¹ = (6.63 × 10⁻³⁴ J.s) . (3.00 × 10⁸ m/s) . (1.495 × 10⁶ J)⁻¹ = 1.33 × 10⁻³¹ m
This wavelength corresponds to the Gamma rays region of the spectrum.
