Term Symbols

Electronic Spectra

Cu(H2O)62+Co(H2O)62+Ni(H2O)62+Fe(H2O)62+Warna akibat adanya transisi elektronik dari satu tingkat energi ke tingkat energi yang lebih tinggi

Electronic spectra (UV-vis spectroscopy)

Beer-Lambert Law

log(I/I0) =A = lc : Absorbance

I/I0 : transmittance : molar absorptivity (L mol-1cm-1)absorption spectrum of [Cu(H2O)6]2+

Electronic configurations of multi-electron atomsWhat is a 2p2 configuration?n = 2; l = 1; ml = -1, 0, +1; ms = 1/2Many configurations fit that descriptionThese configurations are called microstatesand they have different energiesbecause of inter-electronic repulsionsStrategy to understand the electronic spectra of complexes1. Determine free-ion (or in uniform field) term symbols.2. Determine how these terms split in a weak field.3. Determine how these terms split in a strong field.4. Correlate these with Tanabe-Sugano diagram.

Terms : energy levels (or states) of a particular configurationQuantum numbers of single electron atoms (ions)

n : Bilangan Kuantum Utama Menunjukkan tingkat energi elektron (kulit)L : Bilangan Kuantum Azimuth Menunjukkan subtingkat energi elektron (subkulit) l = 0, , sampai (n 1)ml : Bilangan Kuantum Magnetik Menunjukkan orbital m = l, , sampai + lms : Bilangan Kuantum Spin Menunjukkan arah putar pada porosnya (spin)s = + atau = s = atau =

Quantum numbers of multielectron atoms (ions)interaksi (kopling) antara elektron Russell-Saunders coupling (L-S coupling)a. Orbit-orbit interaction (coupling) : ML = m1 L : total orbitalb. Spin-spin interaction (coupling) : MS = ms S : total spinc. L-S coupling : J = L + S : total angular moment quantum numberTerm symbol2S+1LJ2S+1 : spin multiplicityStates : L = 0 (S), 1(P), 2(D), 3(F), 4(G), 5(H), 6(I),...Determining the microstates for p2

Spin multiplicity 2S + 1Determining the values of L, ML, S, Ms for different terms

1S2PClassifying the microstates for p2Spin multiplicity = # columns of microstates

Next largest ML is +1,so L = 1 (a P term)and MS = 0, 1/2 for ML = +1,2S +1 = 33POne remaining microstate ML is 0, L = 0 (an S term)and MS = 0 for ML = 0,2S +1 = 11SLargest ML is +2,so L = 2 (a D term)and MS = 0 for ML = +2,2S +1 = 1 (S = 0)1D

Largest ML is +2,so L = 2 (a D term)and MS = 0 for ML = +2,2S +1 = 1 (S = 0)1DNext largest ML is +1,so L = 1 (a P term)and MS = 0, 1/2 for ML = +1,2S +1 = 33PML is 0, L = 0 2S +1 = 11Sp2ML & MSMicrostateTableStates (S, P, D)Spin multiplicityTerms3P, 1D, 1SGround state term3P

Determine of ground state:

Term dengan multiplisitas lebih besar tingkat energinya adalah lebih rendah dibandingkan term dengan multiplisitas lebih kecilBeberapa term dengan dengan multiplisitas yang sama, tingkat energinya semakin rendah dengan bertambah besarnya harga momentum sudut orbital total (L).

Selection rules(determine intensities)Laporte ruleg g and u u forbidden (that is, d-d forbidden)but g u and u g allowed (that is, d-p allowed)Spin ruleTransitions between states of different multiplicities forbiddenTransitions between states of same multiplicities allowed