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

2. eEDM science state 3Δ1 is ground state
Broadband velocity modulation spectroscopy ( 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)

3. (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

4. 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

5. 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)

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

7. Photo-ionization via core-nonpenetrating Rydberg state② ①

8. 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 JHU

9. 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

10. 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,
Kay, J. J., Coy, S. L., Petrović, V. S., Wong, B. M., R.W. Field. (2008). JCP, 128(19),
Kay, J. J., Coy, S. L., Wong, B. M., Jungen, C., R.W. Field. (2011). JCP, 134(11),

11. LIF experimental apparatus

12. LIF survey spectra from 19200-20400 cm-1

13. 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
(2)
0.223(4)
19.83
(2)
0.227(3)
19.79[1]
(3)
0.219(4)
19.79[2]
(4)
1/2
0.215(4)
20.44
(2)
0.221(3)
38.55
(18)*
0.219(7)
ThF
X 1Σ
0.333(3)
19.54
(2) 1
0.332(3)
ThO
X 1Σ(?)
0.273(3)
19.10
(2)
0.274(3)
19.19
(3)
0.276(3) ?

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