EPR Flashcards
Types of EPR coordinates
Hyperfine: electron and nucleus
Electron Zeeman: electron and magnet
Nuclear Zeeman: nuclear and magnet
Equation for magnetic dipole
(-) g factor x bohr magnetion x spin
What is EPR spectroscopy
Unpaired electron, using the magnetic field of microwave radiation
Electron Zeeman Equation
g value x bohr magneton x magnetic field x spin
KEY: reference sample to determine g value
g ref x B ref / B sample
KEY: g value from data
planks x frequency / Bohr magneton x B
Nuclear Zeeman equation
g(N) x nuclear magneton x magnetic field x spin
Hyperfine interactions equation
Spin (e) x Hyperfine x spin (nuc)
How do you predict spectra using trees
Largest splitting closest to radical
Branches into next closest atoms (do both even if in same environment)
Ratio gives intensities
KEY: How do you predict spectra using equations
Nuclear spin = 1/2
Lines = 2 x number of equiv nuclei x spin + 1
Intensity is Pascal’s triangle
Nuclear spin = 1
Intensity is form of Pascal’s triangle
How to tell if doublet of triplets OR triplet of doublets
The one with the biggest splitting is the first word ie that environment is a doublet so it’s a doublet of triplets
Rules for interpreting spectra from STRUCTURE
Find number of different nuclear environments
Use 2nI+1 to predict
Rules for interpreting spectra from SPECTRA
Work from outside in
Measure separation between first two lines: Hyperfine
Look at intensity
Measure separation distance to next line
If same it’s the same multiplet if not they have overlapped
J value at centre of multiplet
How to find electronic structure
Find theoretical Hyperfine values
Find electron spin density
Find radical distribution
Draw orbital structure
Theoretical Hyperfine values
Constants calculated and dependent on nuclear and electronic wavefunction
