We describe the first precision measurement of the electron's electric dipole moment (eEDM, de) using trapped molecular ions, demonstrating the application of spin interrogation times over 700 ms to achieve high sensitivity and stringent rejection of systematic errors. Through electron spin resonance spectroscopy on 180 Hf 19 F + in its metastable 3 ∆1 electronic state, we obtain de = (0.9 ± 7.7stat ± 1.7syst) × 10 −29 e cm, resulting in an upper bound of |de| < 1.3 × 10 −28 e cm (90% confidence). Our result provides independent confirmation of the current upper bound of |de| < 9.3 × 10−29 e cm [J. Baron et al., Science 343, 269 (2014)], and offers the potential to improve on this limit in the near future.A search for a nonzero permanent electric dipole moment of the electron (eEDM, [3][4][5][6][7][8][9].The most precise eEDM measurements to date were performed using thermal beams of neutral atoms or molecules [3][4][5]. These experiments benefited from excellent statistical sensitivity provided by a high flux of neutral atoms or molecules, and decades of past work have produced a thorough understanding of their common sources of systematic error. Nonetheless, a crucial systematics check can be provided by independent measurements conducted using different physical systems and experimental techniques. Moreover, techniques that allow longer interrogation times offer significant potential for sensitivity improvements in eEDM searches and other tests of fundamental physics [10].In this Letter, we report on a precision measurement of the eEDM using molecular ions confined in a radio frequency (RF) and our use of an RF trap allow us to attain spin precession times in excess of 700 ms -nearly three orders of magnitude longer than in contemporary neutral beam experiments. This exceptionally long interrogation time allows us to obtain high eEDM sensitivity despite our lower count rate. In addition, performing an experiment on trapped particles permits the measurement of spin precession fringes at arbitrary free-evolution times, making our experiment relatively immune to systematic errors due to initial phase shifts associated with imperfectly characterized state preparation.Our apparatus and experimental sequence, shown schematically in Fig. 1, have been described in detail previously [11,12,[18][19][20][21]. We produce HfF by ablation of Hf metal into a pulsed supersonic expansion of Ar and SF 6 . The reaction of Hf with SF 6 produces HfF, which is entrained in the supersonic expansion and rovibrationally cooled through collisions with Ar. The resulting beam enters the RF trap, where HfF is ionized with pulsed UV lasers at 309.4 nm and 367.7 nm to form HfF + in its 1 Σ + , v = 0 ground vibronic state [19,20]. The ions are stopped at the center of the RF trap by a pulsed voltage on the radial trap electrodes, then confined by a DC axial electric quadrupole field and an RF radial electric quadrupole field with frequency f rf = 50 kHz. We next adiabatically turn on a spatially uniform electric bias field E rot ≈ 24 V/c...

Intense single-cycle THz pulses resonantly interacting with molecular rotations are shown to induce field-free orientation and alignment under ambient conditions. We calculate and measure the degree of both orientation and alignment induced by the THz field in an OCS gas sample, and correlate between the two observables. The data presents the first observation of THz-induced molecular alignment in the gas phase.

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The transannular diphosphorus bisanthracene adduct P2A2 (A = anthracene or C14H10) was synthesized from the 7-phosphadibenzonorbornadiene Me2NPA through a synthetic sequence involving chlorophosphine ClPA (28-35%) and the tetracyclic salt [P2A2Cl][AlCl4] (65%) as isolated intermediates. P2A2 was found to transfer P2 efficiently to 1,3-cyclohexadiene (CHD), 1,3-butadiene (BD), and (C2H4)Pt(PPh3)2 to form P2(CHD)2 (>90%), P2(BD)2 (69%), and (P2)[Pt(PPh3)2]2 (47%), respectively, and was characterized by X-ray diffraction as the complex [CpMo(CO)3(P2A2)][BF4]. Experimental and computational thermodynamic activation parameters for the thermolysis of P2A2 in a solution containing different amounts of CHD (0, 4.75, and 182 equiv) have been obtained and suggest that P2A2 thermally transfers P2 to CHD through two competitive routes: (i) an associative pathway in which reactive intermediate [P2A] adds the first molecule of CHD before departure of the second anthracene, and (ii) a dissociative pathway in which [P2A] fragments to P2 and A prior to addition of CHD. Additionally, a molecular beam mass spectrometry study on the thermolysis of solid P2A2 reveals the direct detection of molecular fragments of only P2 and anthracene, thus establishing a link between solution-phase P2-transfer chemistry and production of gas-phase P2 by mild thermal activation of a molecular precursor.