Second generation of JILA eEDM with trapped ThF+ ions Yan Zhou Cornell/Ye JILA eEDM collaboration

eEDM science state 3Δ1 is ground state Broadband velocity modulation spectroscopy (700-1000 nm) 3Δ1 state is 314 cm-1 lower than 1Σ+ state 3Δ1 v+=0, J+=1 lifetime Limited by the blackbody radiation induced rotation/vibration excitation For 300 K, τ ~ 50 s Cryogenic temperature, τ ~ several minutes Daniel N. Gresh, etc., JMS, 319 (2016), 1-9 Barker, B. J, etc., JCP, 136, (2012) 104305.

(Ionization selectivity) Comparison of HfF+ and ThF+ ThF+ HfF+ 3Δ1 0 cm-1 977 cm-1 1Σ+ 314 cm-1 Coherence ~50 s 2 s Two-photon Doppler ~1 MHz ~3 MHz Internal E field 35.2 GV/cm 23.4 GV/cm Omega doubling 5.2 MHz 740 kHz Dipole moment 1.6 e a0 (theory) 1.401(5) e a0 (exp.) Hyperfine splitting Unknown 45.5 MHz (Ionization selectivity) Yes No Longer coherence time Larger internal E field Better state preparation 100x statistical sensitivity improvement

Working list Highly J-selective photo-ionization (1Σ+, v+=0, J+=0) Efficient state preparation for Ramsey spectroscopy (F=3/2, mF=±3/2, N=±1) Efficient signal readout - REMPD Paul trap or storage ring for homogeneous Erot > 40 V Long coherence time Multiplexing measurements

Vibrational autoionization from Rydberg states - HfF “shake-off” ionization 1S+ HfF+ 357nm 1mJ J-selectivity: ~30% (<10% direct impact ionization) Autoionization vs. direct ionization: adiabatic vs. diabatic [32.3]0.5 309nm 5uJ HfF X2Δ3/2 No direct collision between Rydberg electron and ion-core Narrower spectroscopic lines (<<2B)

What is core-nonpenetrating Rydberg state ℓ ℓR N+ Λ (ℓ) N Hund case (b) Hund case (d) CNP

Photo-ionization via core-nonpenetrating Rydberg state ② ①

Ionic electronic state Searching d-f transitions Th+ F- 2 A 6d7s2 Closed shell 1 A Ionic electronic state 4Φ9/2, 4Φ7/2 , 4Φ5/2 , 4Φ3/2 2Φ7/2, 2Φ5/2 4∆7/2, 4∆5/2, 4∆3/2, 4∆1/2 2∆5/2, 2∆3/2 4∏5/2, 4∏3/2, 4∏1/2 2∏3/2, 2∏1/2 2Σ1/2, 4Σ3/2 2Φ7/2, 2Φ5/2 2Δ5/2, 2Δ3/2 2Π3/2, 2Π1/2 2Σ1/2 6d7snp nf7s2 Ionic electronic structure Single-electron promotion Strict selection rule: ΔΩ=0,±1 “Good” selection rule: ΔΛ=0,±1, ΔS=0 X 2∆3/2, 6d7s2 Vibrational frequency: ωe(s2f) > ωe(spd) Ligand Field Theory Hyperfine structure (Hhyper(s2f)<<Hhyper(spd)) Electric Dipole Moment (μ(s2f)<<μ(spd)) Prof. Lan Cheng @ JHU

Searching CNP Rydberg states CNP Rydberg state is extremely sensitive to DC electric field! BaF Rydberg spectrum (mmW) Yan Zhou, R.W. Field, etc., (2015). CPL, 640, 124

Searching CNP Rydberg states Simulated spectra with CaF model Search for CNP Rydberg state with Stark demolition Detuning/cm-1 Intensity/arb.u. g h Π Petrović, V. S., Kay, J. J., Coy, S. L., R.W. Field. (2009). JCP, 131, 064301. Kay, J. J., Coy, S. L., Petrović, V. S., Wong, B. M., R.W. Field. (2008). JCP, 128(19), 194301 Kay, J. J., Coy, S. L., Wong, B. M., Jungen, C., R.W. Field. (2011). JCP, 134(11), 114313

LIF experimental apparatus

LIF survey spectra from 19200-20400 cm-1

Fittings of LIF spectra 15 strong molecular transitions 3 transitions do not have clear diatomic PQR pattern 3 transitions are not very reproducible nu0 Ω B X 2Δ 3/2 0.237(3) 19.92 19924.5(2) 0.223(4) 19.83 19829.4(2) 0.227(3) 19.79[1] 19787.3(3) 0.219(4) 19.79[2] 19789.5(4) 1/2 0.215(4) 20.44 20443.6(2) 0.221(3) 38.55 38547.2(18)* 0.219(7) ThF X 1Σ 0.333(3) 19.54 19539.1(2) 1 0.332(3) ThO X 1Σ(?) 0.273(3) 19.10 19098.7(2) 0.274(3) 19.19 19191.0(3) 0.276(3) ?

Acknowledgement Matt Grau Daniel Gresh William Cairncross Kevin Cossel Kia Boon Ng Yiqi Ni Eric Cornell Jun Ye Bob Field Michael Heaven Timo Fleig