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

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-

Lanthanide Oxide Dipole moments UO=3.363D 3.31D ↓

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-

NdO [16.7]3 – X4 Transition P(4) Q(4)

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

Stark Analysis Results The Stark shifts (first-order perturbation theory H=-mE ): Results State   (D) Correlation Matrix Std. dev (MHz) X(1)4 2.820(09) 1.00 [16.7]3 3.114(10) 0.89 1.00 16 Changed spelling for correlation and matrix -10-

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

Dipole Moment Trends in Lanthanide Oxides

Trend in effective nuclear charge (μ/Re)

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

Zeeman Analysis Results The Zeeman shifts (first-order perturbation theory H=-mB): Results State J geff Correlation Matrix Std. dev.(MHz) X(1)4 4 2.116(6) 1.00 [16.7]3 3 2.084(6) 0.86 1.00 [16.7]3 4 2.178(8) 0.90 0.78 1.00 11 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-

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

For f3(4I4.5)s configuration B = 3Jf(Jf+1)+Sf(Sf+1)-Lf(Lf+1) = 3*4.5*5.5+1.5*2.5-6*7 = 36 D=3j(j+1)+s(s+1)-l(l+1) = 3*0.5*1.5+0.5*1.5-0 = 3.0

NdO geff Calculation geff calculated = 2.11; experiment = 2.116(6) Allouche et al [JCP 124 184317 (2006)] Composition of ground state X(Ω=4) of NdO is 90%(5I) + 8%(5H) + 1%(5Γ) + 1%(3H) geff = Λ + 2.002Σ 0.90x2.00 + 0.08x3.00 + 0.01x4.00 + 0.01x3.00 geff calculated = 2.11; experiment = 2.116(6) Also calculated net charge ~ 0.5e → μ ~ 4.2D

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