The “Light” side of chemistry: The Photochemistry

Abstract

Sunlight is a part of the radiation from the sun in the form of elecromagnetic waves. These elecromagnetic waves are infrared, visible, and ultraviolet. The atmosphere around the earth is helping to filter the sunlight. The earth receives the filtered sunlight. It is obvious as daylight when the sun is above the horizon. The earth use to experience the sunshine, which is combination of the bright light and radiant heat. This type of experience of the earth is only when the direct solar radiation is not blocked by clouds. On the other hand, diffused light is the effect of blocking the sunlight by clouds or reflects off other objects. The sunshine duration or sunshine hours is the indicator of climatology according to the World Meteorological Organization. It is the cumulative time (hours). During the sunshine duration or sunshine hours, the given area on earth receives direct irradiance from the Sun of at least 120 watts per square meter. The average over the entire earth of 164 Watts per square meter over a 24 hour day is according to the other sources. It require about 8.3 minutes for Sunlight to reach earth from the surface of the sun. A photon is the elementary particle of the sunlight. The photon is starting at the center of the sun. The photon use to change the direction every time. The photon encounters a charged particle and it would take between 10,000 and 170,000 years to get to the surface. For the photosynthesis to proceed, the sunlight is a key factor. The photosynthesis is the process used by plants and other autotrophs for the purpose to convert sunlight energy into chemical energy. This chemical energy is used for the purpose to synthesize the food material in the form of carbohydrates. The sunlight is acting like a wave, with a specific frequency and specific wavelength. The sunlight wave frequency and the wave length of sunlight are related by the speed of sunlight. The sunlight wave frequency and the wave length of sunlight are making the speed of sunlight as a constant. The photon of sunlight is acting like energy particle. The value of this energy particle is related to the frequency of light.

Key Words: Photoexcitation; Photon; Fluorescence; phosphorescence; Photochemistry; Light