Chemical actinometry (IUPAC Technical Report)

TLDR

This document updates the first IUPAC technical report on chemical actinometers, noting improvements, modified procedures, new substances, and defining an actinometer as a system or device that determines the number of photons absorbed in a reactor. The compilation includes chemical actinometers for gas, solid, microheterogeneous, and liquid phases, as well as for pulsed‑laser measurements of transient absorbances and quantum yields, and provides literature for each. The actinometers cover the UV to red spectrum, with recommended standard procedures and methods for absolute photon‑flux measurement using photodiodes. Advantages and disadvantages of chemical actinometers versus electronic devices for measuring absorbed photons are discussed. Chem.

Abstract

This document updates the first version of the IUPAC technical report on “Chemical actinometers” published in Pure Appl. Chem . 61 ,187-210 (1989). Since then, some methods have been improved, procedures have been modified, and new substances have been proposed as chemical actinometers. An actinometer is a chemical system or a physical device by which the number of photons in a beam absorbed into the defined space of a chemical reactor can be determined integrally or per time. This compilation includes chemical actinometers for the gas, solid, microheterogeneous, and liquid phases, as well as for the use with pulsed lasers for the measurement of transient absorbances, including the quantum yield of phototransformation, as well as the literature for each of the actinometers. The actinometers listed are for the use in the wavelength range from the UV to the red region of the spectrum. A set of recommended standard procedures is also given. Advantages and disadvantages are discussed regarding the use of chemical actinometers vs. electronic devices for the measurement of the number of photons absorbed. Procedures for the absolute measurement of incident photon flux by means of photodiodes are also discussed.