Electronic Spectroscopy: UV and Visible Absorption

The process where a molecule releases energy by transitioning from a higher energy level to a lower energy level, often resulting in the emission of light.

The absorption of photons in the ultraviolet-visible (UV-Vis) region of the electromagnetic spectrum is the primary cause of electronic excitation in molecules.

The highest occupied molecular orbital (HOMO) is the molecular orbital from which an electron is promoted during electronic excitation.

A chromophore is a group of atoms in a molecule that absorbs light, regardless of whether it produces a visible color.

Nonradiative decay refers to the transition of a molecule from a higher energy level to a lower energy level without the emission of radiation.

Electronic excitation of molecules predominantly occurs in the ultraviolet and visible regions of the electromagnetic spectrum.

The presence of a chromophore is a prerequisite for a molecule to exhibit an electronic spectrum, as it is the chromophore that absorbs light.

Electronic excitation typically involves the transition of an electron from the HOMO to the LUMO (lowest unoccupied molecular orbital).

Electronic excitation in molecules typically occurs in the energy range of 10^14 to 10^16 kJ/mol.

Absorption refers to the process where a molecule absorbs a photon of UV-visible light, causing an electron to transition to a higher energy level.

The color observed in a molecule that absorbs visible light arises from the specific wavelength of light that it absorbs.

Vibrational transitions are not considered electronic transitions, as they involve changes in the vibrational energy levels of a molecule, not the electronic energy levels.

Electronic transitions are not always accompanied by the emission of light. Nonradiative decay is an example of an electronic transition that doesn't produce light.

Cosmic rays, with the highest energy levels in the electromagnetic spectrum, carry the most energy out of all forms of radiation.