do not use the relationship between the kinetic energy and the photonic energy,, I do not know the how to solve this problem using particle in a box and 0.139 nm .

5. (20pts) Estimate the absorption wavelength (one electron excitation by absorbing photon energy) of 1,4 diphenyl-1,3-butadiene. Consider the two benzene rings in the molecule as the wall in the particle in a box model and assume that the relevant carbon-carbon bonds in conjugated organic molecule are each 0.139 nm long. Electron mass = 9.11x10-31 kg, speed of light = 2.99x109 m/s, Plank constant = 6.626x10-34 Js. = =