Rate of ISC Formula:
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Definition: The rate of ISC is the rate of an isoenergetic radiationless process involving a transition between two electronic states with different spin multiplicity.
Purpose: This calculator helps determine the rate at which molecules transition from the singlet excited state to the triplet state.
The calculator uses the formula:
Where:
Explanation: The rate is calculated by multiplying the rate constant by the concentration of molecules in the singlet excited state.
Details: Understanding ISC rates is crucial in photochemistry, molecular spectroscopy, and the design of optoelectronic materials.
Tips: Enter the rate constant (KISC) in Hz and the singlet state concentration in mol/m³. All values must be > 0.
Q1: What is a typical value for KISC?
A: Typical values range from 106 to 1012 Hz depending on the molecule and conditions.
Q2: How is singlet state concentration determined?
A: It can be measured experimentally using absorption or fluorescence spectroscopy techniques.
Q3: What factors affect the ISC rate?
A: Molecular structure, solvent effects, temperature, and heavy atom presence can all influence ISC rates.
Q4: What's the difference between ISC and internal conversion?
A: ISC involves a change in spin multiplicity, while internal conversion occurs between states of the same multiplicity.
Q5: How does ISC relate to phosphorescence?
A: ISC populates the triplet state which can then decay via phosphorescence.