Related Experiment Video
Updated: Dec 10, 2025

Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch
Published on: February 7, 2022
A Master Equation for Photochemical Rates
1Bolton Photosciences Inc., Edmonton, AB, Canada.
Abstract:
Traditionally, the general photochemical rate equation could be integrated only at two limits (high concentration and low concentration). In this paper, the general photochemical equation has been integrated to yield a master equation that is valid for any chromophore concentration. Hence, in future, data for all concentrations can be utilized in deriving the incident photon flux and/or the quantum yield for a photochemical reaction. Unfortunately, the master equation can only be used for monochromatic light sources.
Related Concept Videos
Multi-Step Reactions
Rate-Determining Steps
In a multistep reaction mechanism, one of the elementary steps progresses significantly slower than the others. This slowest step is called the rate-limiting step (or rate-determining step). A reaction cannot proceed faster than its slowest step, and hence, the rate-determining step limits the overall reaction rate.
The concept of rate-determining step can be understood from the analogy of a 4-lane freeway with a short-stretch of traffic-bottleneck caused due to...
The Photochemical Reaction Center
Reaction Rate
The mathematical representation of the change in the concentration of reactants and products, over time, is the rate...
Reaction Mechanisms
For instance, the decomposition of ozone appears to follow a mechanism with two steps:
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation

