Chemistry Lecture Notes UV

1. Chemistry Lecture Notes UV

2. Wavelengths for newcomers • Malcolm Solomon of Palo Alto, Calif., pointed out a column by Lloyd Oakley in the August issue of Psychic Reader's (Déjà Vu Publications, Berkley, CA). Oakley, who is billed as "a clairvoyant and a caterer," begins by stating, “Sunlight is an important part of one's diet.” In enlarging on this theme he gives “some simplified versions of how the different wavelengths of light effect [sic] you. The scale of light rays or waves can be divided into three easy-to-understand groups: • Below 400 nm per second is infrared. This is heat. • Between 400 and 700 nm per second is ultraviolet light. Color, or the rainbow, falls into this category. • Light traveling more than 700 nm per second is gamma radiation—the stuff in science fiction movies. Inappropriate amounts of this light are not good for the body—too much and you might turn into a large green turtle.”

3. Absorption of light in conjugated systems molecular orbitals: ground state excited state conjugated double bonds smaller DE  lower frequency, longer wavelength

4. Photochromism a naphthopyran derivative closed form colorless (less conjugation, absorbs in UV) open form colored (more conjugation, absorbs in visible)

5. Vitamin D and sunlight vitamin D3 is involved in the regulation of calcium and phosphorus metabolism - essential for preventing rickets