Quantum Chemistry 3.8 - UV-Vis Spectra of Polyenes

Short lecture on the ultraviolet-visible spectra of polyenes. The electrons of the pi systems of conjugated linear polyenes can be approximated as non-interacting particles in a box. The length of the box is determined by the sum of the bond lengths. Electrons occupy the particle in a box states according to the Aufbau principle with two electrons per level. In ultraviolet-visible spectroscopy, a photon in that frequency range of the electromagnetic spectrum excites an electron from the HOMO to the LUMO. The wavelength of maximum absorption is approximately proportional to the size of the system, in qualitative agreement with experimental values. Notes Slide: http://i.imgur.com/3eVmqm8.png -- About TMP Chem -- All TMP Chem content is free for everyone, everywhere, and created independently by Trent Parker. Email: tmpchemistry@gmail.com -- Video Links -- Chapter Playlist:    • Particle in a Box / Schrodinger Equation   Course Playlist:    • Quantum Chemistry and Spectroscopy   Course Review:    • Quantum Chemistry Chapter Reviews   Other Courses:    • PChem Course Intros   Channel Info:    • About TMP Chem   -- Social Links -- Facebook:   / tmpchem   Twitter:   / tmpchem   LinkedIn:   / tmpchem   Imgur: https://tmpchem.imgur.com GitHub: https://www.github.com/tmpchem -- Equipment -- Microphone: Blue Yeti USB Microphone Drawing Tablet: Wacom Intuos Pen and Touch Small Drawing Program: Autodesk Sketchbook Express Screen Capture: Corel Visual Studio Pro X8