what cm-1 do electronic transitions occur at
from 10,000 to 50,000 cm-1
in electric spec,, why do absorptions occur
- ligand spectra ( pi to pi* // n to pi*) intense
- counter ion spec ( n to pi*)
- charge transfer spec (MLCT,LMCT) moderate
- ligand field spec (d to d) weak signal,, low energy
why do d d transitions have a low signal and therefore a low energy
bc they are forbidden bc they dont follow all of the rules.
aka the spin needs to be 0
the change in L needs to be 1
and in ccs there needs to be a change in symmetry from ug to g etc.
in dd transitions theres no change in L and there can be a change in spin?
if ere given smt in nm and we want to find it in cm-1,, what do we do
10^7 / nm = cm-1
what do we need to consider in ligand field spec
we need to consider different electron arrangements in the d orbitals
how do we consider different electron arrangements in ligand field spec
we think of russel saunders coupling to find the ground // state terms arising from different dn configurations.
when we do russel saunders,, what do we need to max out
we need to max out L and S,, but we prioritise S,, so we put the e- in the highest ml values but we dont pair them up. unless ur doing like a weird excited state or smt
whats a state term
u have L as a big number
then u have 2s+1 in the top left
where s is the spin so u just add or take away 1/2s.
whats s in terms of numbers
0
whats p in terms of numbers
1
whathappens to ground state terms when a ligand field is applied
they split
aka the ground states are split
what gives rise to absorbance bands in spec
absorbance
aka a transition between two energy levels.
so if u have 2 energy levels ur state symbol splits into ,, u can only transition between those 2,, so u will only have one absorption band.
what L term also has a P term at a higher energy level
the F term also has a P energy level at a higher energy level.
if the F term asl ohas a P symbol meaning it splits into 3 different enrrgy levels when a field is applied,, what does this mean
it means thetre are more transitions available as there are more energy levels for the transition to occur between,
this means that there can be 3 absorbance bands instead of 2!!
in Oh symmetry,, the F st`te symbol splits intno how many energy levls
it splits into 4 different energy levels,, meaning there can be 3 different transitions.
d1 splits into whanormally,, d orbitals split into what
d orbitals split into t2g and eg.
2D splits into what energy levels
2Eg and 2T2g
Eg for the excited state,, and T2g for the ground state
whats the energy diff between t2g and eg,,
its just delta.
what does the big letter in the term descirbe
it describes the arrangement of the e-.
whats hole formalism
its the like electron and hole thing. meaning d1 and d9 have hole formalism bc d1 has 1 electron and d9 has one hole; so theyre connected but also not rlly.
d9 can split into what
t2g and eg
d1 can split into
t2g and eg
dn is the opposite offff
d10 - n
dn and what is equal
dn and dn+5 are equal!!
