1. 62nd International Symposium on Molecular Spectroscopy, Columbus, Ohio, June 2007
The Permanent Electric Dipole Moment and Magnetic g-factors of Neodymium Monoxide, NdO
Colan Linton
University of New Brunswick, Canada
Tongmei Ma, Hailing Wang and Timothy C. Steimle
Arizona State University, USA
Got rid of the middle initial in my name
Funded by: DoE_BES, NSERC

2. Goals Determine permanent electric dipole moments, m
Determine magnetic g-factors
Use results from “1” & “2” to examine configurations, coupling cases and to test theory
LFT model successfully predicts properties of LnO & LnX(X=F,Cl,Br).
Changed spelling for Lanthanide above periodic table
UO ground state predominantly U2+(5f37s)O2- → Ω = 4
Stark → μ = 3.363D: Zeeman → geff = 2.562
NdO → Nd2+(4f36s)O2- → Ω = 4
Dipole moment and geff similar to UO???
-1-

3. Lanthanide Oxide Dipole moments
UO=3.363D
3.31D ↓

4. Optical Stark spectroscopy
Near natural line width optical spectroscopy: High-resolution LIF spectrometer
Stark plates
Optical Stark spectroscopy
Optical Zeeman Spectroscopy
Helmholtz Coils
600 nm (10)
Bandpass Filter
-4-

5. NdO [16.7]3 – X4 Transition
P(4)
Q(4)

6. Optical Stark Spectra of P(4) of NdO
Zero Field +3 -3
ΔMJ=0
E=1543 V/cm // -2 +4
ΔM=-1 -4 +2
ΔMJ=+1
E=1543 V/cm

7. Stark Analysis Results
The Stark shifts (first-order perturbation theory H=-mE ):
Results
State   (D) Correlation Matrix Std. dev (MHz)
X(1) (09)
[16.7] (10)
Changed spelling for correlation and matrix
-10-

8. NdO P(4) Stark Spectra at 1543 V/cm
Calc //
Exp //
Calc ┴
Exp ┴

9. Dipole Moment Trends in Lanthanide Oxides

10. Trend in effective nuclear charge (μ/Re)

11. Zeeman Effect in Q(4) Line of NdO
Zero Field +4 +1 -1 -4
ΔMJ=0
B = 1000G // +4 -3 +3 -4
ΔMJ=-1
ΔMJ=+1
B = 1000G

12. Zeeman Analysis Results
The Zeeman shifts (first-order perturbation theory H=-mB):
Results
State J geff Correlation Matrix Std. dev.(MHz)
X(1) (6)
[16.7] (6)
[16.7] (8)
Spelling for correlation and matrix. Don’t know what picture in middle represents. Also erased the geff= after the equation. Not sure what was meant there
-11-

13. LFT Coupling in the Ω=4 Ground State
For f3s configuration: f3 ground state is 4I4.5
where Lf=6, Sf=1.5 and Jf=4.5
The s electron has l=0, s=0.5, j=0.5
Combining gives 2 states separated by exchange interaction Sf
Total atomic Angular momentum Ja=4 or 5 j Jf
The ground state has Ja=4 Ja Lf
Projection on axis gives Ω=4 Ground State Ω

14. For f3(4I4.5)s configuration
B = 3Jf(Jf+1)+Sf(Sf+1)-Lf(Lf+1) = 3*4.5* *2.5-6*7 = 36
D=3j(j+1)+s(s+1)-l(l+1) = 3*0.5* *1.5-0 = 3.0

15. NdO geff Calculation geff calculated = 2.11; experiment = 2.116(6)
Allouche et al [JCP (2006)]
Composition of ground state X(Ω=4) of NdO is
90%(5I) + 8%(5H) + 1%(5Γ) + 1%(3H)
geff = Λ Σ
0.90x x x x3.00
geff calculated = 2.11; experiment = 2.116(6)
Also calculated net charge ~ 0.5e → μ ~ 4.2D

16. Conclusions NdO ground state dipole moment less than UO
Appears to be significant drop in μ from LaO (zero f electrons) to NdO (3 f electrons)
Need to test to see if trend continues for CeO (fs) and PrO (f2s)
Monotonic increase of μ in lanthanide oxides with addition of f electrons indicative of imperfect shielding
Zeeman effect: Theoretical ground state composition gives excellent prediction for g factor