CHIRALITY DETERMINATION FROM PULSED-JET FOURIER TRANSFORM MOLECULAR STRUCTURE AND CHIRALITY DETERMINATION FROM PULSED-JET FOURIER TRANSFORM MICROWAVE SPECTROSCOPY SIMON LOBSIGER, CRISTOBAL PEREZ, LUCA EVANGELISTI, NATHAN A. SEIFERT, BROOKS H. PATE, KEVIN K. LEHMANN Department of Chemistry, University of Virginia

Background Mirror reflection: sign of mambmc changes E. Hirota, Proc. Jpn. Acad., Sec B, 2012, 88, 120. Background D. Patterson, M. Schnell and J. M. Doyle, Nature, 2013, 497, 475 D. Patterson and J. M. Doyle, Phys. Rev. Lett., 2013, 111, 023008 Mirror reflection: sign of mambmc changes Cycle of three dipole-allowed transitions (a-, b- and c-type) between rotational states: Three-wave mixing experiment Two orthogonally polarized resonant fileds  third mutually orthogonal field encoding the chiral signal and shift 180 degrees between enantiomers

Three Wave Mixing 2 11 2 02 1 01 Coherence Transfer 𝜋 pulse Coherence J.-U. Grabow, Angew. Chem. Int. Ed., 2013, 52, 11698 Three Wave Mixing K. K. Lehmann, unpublished X Z Y Coherence Transfer 𝜋 pulse Ψ = 𝑐 1 (t) 1 01 + 𝑐 2 (𝑡) 2 11 + 𝑐 3 (𝑡) 2 02 2 11 Coherence 2 02 𝜋 2 pulse Ψ = 𝑐 1 (t) 1 01 + 𝑐 2 (𝑡) 2 11 Chiral Signal 1 01 Θ 𝑅𝑎𝑏𝑖 = 𝜔 𝑅𝑎𝑏𝑖 ∙ 𝑡 𝑝𝑢𝑙𝑠𝑒 = − 𝜇∙𝐸 ℏ ∙ 𝑡 𝑝𝑢𝑙𝑠𝑒 𝑃 𝑋 ∼𝝁 𝒂 𝝁 𝒃 𝝁 𝒄 1 01 Φ 𝑋𝑧 2 02 2 02 Φ 𝑌𝑥 2 11 2 11 Φ 𝑍𝑦 1 01 Considerations: -Signal a DP of p/2 pulse -Signal a [nChiral Signal][mChiral Signal] -Q-Branch involved (low frequency)

Experimental setup X Z Y Z Y X

R S Solketal 𝝁 𝒂 -1.8 D 1.8 D 𝝁 𝒃 1.2 D 1.2 D 𝝁 𝒄 -0.2 D -0.2 D m06-2x/6-311++g(d,p) A = 2756 MHz B = 1248 MHz C = 1088 MHz 𝝁 𝒂 -1.8 D 1.8 D 𝝁 𝒃 1.2 D 1.2 D 𝝁 𝒄 -0.2 D -0.2 D 𝝁 𝒂 𝝁 𝒃 𝝁 𝒄 + -

Broadband spectrum 2-8 GHz Measured Noise Level: 0.4 mV 400,000 Averages a-type (4604 MHz) b-type (1839 MHz) c-type (6443 MHz) 1.5K Simulation of Solketal Rotational Spectrum Fit Substitution Structure from 13C and 18O Isotopic Analysis (Natural Abundance) m06-2x/6-311++g(d,p) mp2/6-311++g(d,p) * Cristóbal Pérez, Simon Lobsiger, Nathan A. Seifert, Daniel P. Zaleski, Berhane Temelso, George C. Shields, Zbigniew Kisiel, and Brooks H. Pate, “Broadband Fourier Transform Rotational Spectroscopy for Structure Determination: The Water Heptamer (Frontiers Article)”, Chem. Phys. Lett. 571, 1-15 (2013).

Experimental Design & Implementation 2 11 2 02 𝜋 pulse 𝜋 2 pulse b-type (1839 MHz) a-type (4604 MHz) 1 01 c-type (6443 MHz) R-Branch weakest dipole moment MW power DP Detection in the strongest 𝜋 pulse Second weakest (Q-Branch)

Rabi Excitation Characteristics 𝜇 𝑎 = 1.8 D 𝜇 𝑏 = 1.2 D 𝜇 𝑐 = 0.2 D 𝜋 2 pulse Θ 𝑅𝑎𝑏𝑖 = 𝜔 𝑅𝑎𝑏𝑖 ∙ 𝑡 𝑝𝑢𝑙𝑠𝑒 = − 𝜇∙𝐸 ℏ ∙ 𝑡 𝑝𝑢𝑙𝑠𝑒

Rabi Excitation Characteristics 𝜇 𝑎 = 1.8 D 𝜇 𝑏 = 1.2 D 𝜇 𝑐 = 0.2 D 𝜋 pulse Θ 𝑅𝑎𝑏𝑖 = 𝜔 𝑅𝑎𝑏𝑖 ∙ 𝑡 𝑝𝑢𝑙𝑠𝑒 = − 𝜇∙𝐸 ℏ ∙ 𝑡 𝑝𝑢𝑙𝑠𝑒

Spectrum of Chiral Signal 2 11 2 02 𝜋 pulse 𝜋 2 pulse b-type (1839 MHz) a-type (4604 MHz) 1 01 c-type (6443 MHz) Directly Digitized 50Gs/s Filtered Frequencies

Enantiomer Dependent Phase 11

Carvone: New conformer EQ3 Absolute Phase Measurements Solketal Carvone: New conformer EQ3 Others EQ2 EQ1 EQ3

Conclusions Easy to implement at higher frequency Three wave mixing: Time separated pulses tested successfully Best Implementation: Optimal sequence 𝜋 2 pulse to create coherence 𝜋 pulse coherence transfer Sizeable Chiral Signals Issues with the absolute phase determination.

Thanks for your attention!! Acknowledgements National Science Foundation (NSF) grants CHE-0960074. Kevin Lehmann Thanks for your attention!!

Spectrum of Chiral Signal Fit of both MW pulses. Product generates a “marker” that can be directly compared to the filtered molecular signal. Phase can be compared across the FID

Absolute Phase Measurements fR = -2.14(67) fS = 1.29(84)