Physical 6

Physical 6

1. vibrational levels

   • lowest electronic state
     • labelled by v'' quantum number
   • upper electronic state
     • labelled by v' quantum number

2. vibronic transitions

   • transitions between vibrational and electronic states
   • allow symmetry

3. deslanders table

   • assign vibronic transitions
   • difference is 2x
   • difference in rows is ωe'
     • difference in columns ωe''
   • difference between minima of curves
     • v0,0-1/2ωe'+1/2ωe''
   • X = ground state; B = excited state
     • A = excited state from pi orbital
   • z=ωe''-2ωe''

4. photoelectron spec

   • measures the ionisation energy
     • electrons are ejected by absorption of a photon of known energy
   • vaccum UV radiation photodetatch electrons
     • from valence orbitals
   • x-ray uses higher energy radiation to phtotodetach electrons
     • from core orbitals
   • kinetic energy measured and converted to ionisation energy

5. harmonic oscillator

   • vibrational energy levels are equally spaced
     • by vibrational wavenumber
       • ωe=1/2πc √(k/μ)
     • energy spacing between adjacent (v & v+1)-remain constant
       • with increasing potential energy

6. morse potential

   • vibrational energies spacings get smaller
     • higher energies
     • broadening well
     • with increasing potential energy
   • anharmonic correction: ωeχe
     • potential energy=( v+1/2)ωe - v+1/2)^2ωe

7. absorption spec

   • T=It/I0
   • A=log I0/It=εcl
   • incident light induces vibronic transitions
   • promotes an electron from bonding to antibonding
   • equilibrium bond lengths of ground and excited are different

8. adiabiatic transitions are 0,0

   • when bond order is unchanged with excited state