1. TALKING DIRECTLY TO RYDBERG STATES Yan Zhou, David Grimes, Ethen Klein, Timothy Barnum, Robert Field laser mmW

2. Global model MOS seminar 2014.4.222 Valence state (v, N) Core-penetrating Rydberg state (v, N) = Σ(v+, N+, l) Core-nonpenetrating Rydberg state (v+, N+, l) laser mmW Completely coupled Partially decoupled Several ion states Completely decoupled One ion state Physics Ion-core isolated from the outside world Chemistry Strong Ion-electron collisions Multichannel collision Electron probes ion molecular ion Global model

3. THz spectroscopy JILA seminar 201406123 CH 3 F H 2 CO Detection sensitivity is low Multiphoton-ionization Lack of narrow band generation (~0.1THz) Experiment seems not to fit Rydberg molecules * Collaborate with Prof. Keith Nelson

4. Millimeter wave spectroscopy Initialized by Prof. Dan Kleppner Resolution -> millimeter-wave JILA seminar 201406124 Unit: MHz 5MHz (b)

5. Difficulties JILA seminar 201406125 Ion detection – Stray electric field – 5MHz resolution Intensity fluctuations Data record: (20GHz / 100kHz) x 1s = 60 hours! Manipulations: Multi-dimensional spectroscopy, 60 n hours! Weapons CPmmW spectrometer 20GHz bandwidth, 50kHz resolution Detection efficiency improvement 10000 Buffer gas cooling molecular beam source Number density improvement 1000 Beam velocity improvement 10 Total improvement: 10 8 !

6. Molecular system - BaF C2ΠC2Π X2Σ+X2Σ+ ~20100 cm -1 ~18600 cm -1 IP 0 =38745 cm -1 n~40, l n-1, l +1 n+1, l +1 v + =0, N + D 0 =48200 cm -1 v + =1 v + =2 200 new transitions / hour Laser resolution: 1 GHz mmW resolution: 50 kHz

7. All people like hydrogen All people like CNP states! Let us go with CNP states only!

8. Stark demolition JILA seminar 201406128 CNP CP CP or CNP 1V/cm CNP, l>4 FID no FID CP CNP CP ~10MHz

9. JILA seminar 201406129 Laser forbidden CNP states laser mmW laser CP CNP

10. CNP-CNP transitions CP, l=3 CNP, l=4 mmW 1 mmW 2 CNP, l=5 Blind search: A pulse sequence with 3 or more 20 GHz chirps Not increase the search time mmW multiple resonances Current work: Collecting all such CNP-CNP transitions mmW 3 CNP, l=6

11. JILA seminar 2014061211 n=41n=42n=43n=44 n=42 n=43 n=44 n=45 n=40 n=41 75-100 GHz 12 cm -1 2B4B Δ l =+1 Δ l =-1 2B4B 2B

12. User friendly assignment recipe JILA seminar 2014061212 No sophisticated pattern recognition and fitting program Most information comes from experiments directly A calculator is enough!

13. Organize transitions (1) Rydberg formula (2) Up/down transitions (3) Stark demolition – CP or CNP CP CNP

14. Thank you for your attention!