The pure rotational spectrum of YbOH

Abstract

The pure rotational spectrum of YbOH has been recorded and analyzed to produce fine and magnetic hyperfine parameters for the 2 (0,0,0) X   state. These parameters are compared with those determined from the optical study [Melville and Coxon, J. Chem. Phys. 115, 6974-6978 (2001)] and with the values for YbF [Dickinson et al. 115, 6979-6989 (2001)]. The results support the existence of an unobserved perturbing state near the ̃2 Π 1/2 state, similar to that previously found in YbF. The precisely determined parameters lay the foundation for laser cooling YbOH, which will aid in the search for new physics beyond the standard model. Introduction Recently, it has been proposed [1] that the linear triatomic molecule YbOH may be a sensitive venue for investigating T-violating physics beyond the standard model (BSM), such as the electron electric dipole moment (EDM) and nuclear magnetic quadrupole moment (MQM) via the heavy Yb atom. When compared to the diatomic molecules currently used in BSM searches, the additional degrees of freedom offered by YbOH provide several advantages. Specifically, YbOH has the coexistence of an electronic structure amenable to laser cooling, and closely spaced opposite parity states useful for systematic error rejection[1], which are not simultaneously offered by diatomic systems suitable for EDM and MQM searches. A precision measurement with laser cooled and trapped YbOH could extend coherence times (the current limitation of molecular beam BSM searches [2-4]) by orders of magnitude, ultimately probing T-violating BSM physics at the PeV scale[1]. The analogous study of laser cooled YbF has been actively pursued for some time [2, 3, 5, 6]. YbOH offers several advantages compared to YbF. First, the metastable (0,1,0) bending mode of YbOH contains closely spaced states of opposite parity, which enables full

Laser-cooled polyatomic molecules for improved electron electric dipole moment searches

“…The SR structure in the S + X 2 state, which arises from interaction with Ω=1/2 excited electronic states, is unusual because the splitting scales quickly with vibrational level (see figure 1(c)). The same effect has been observed in YbF and is attributed to competing contributions from the P A 2 1 2 vibrational states and vibrational levels ofΩ=1/2 excited electronic states arising from an Yb + ( f 13 ) configuration [57,[63][64][65][66]. To address both SR components, we pass each laser beam through an acousto-optic modulator (AOM) which adds a frequency sideband at the appropriate rf interval.…”

“…Note the unusual ordering due to the SR constant, γ, being negative. The hyperfine splittings have been measured previously [57] and are unresolved in optical excitation. 1(b)).…”

“…The proton hyperfine splittings in 174 YbOH are unresolved in optical excitation (<3 MHz, see figure 1(b)). The splittings are small due to the large distance between the hydrogen nucleus and the predominantly metal-centered valence electron [57].…”

Polyatomic molecules as quantum sensors for fundamental physics

“…This means that the parity doublets of polyatomic molecules are a useful resource, and again do not in general interfere with the electronic structure requirements for good sensitivity. NSM sensitivity has been examined for a number of species, including TlCN [133], RaOH [54], RaOH + , and ThOH + [94], along with MQM sensitivity for BaOH [134], LuOH + [135], and YbOH [134,136], which is being pursued for an MQM search in a molecular beam [29,110,113]. All of these sensitivities, like E eff , have so far been quite similar to their fluoride analogues.…”

Fine and hyperfine interactions in 171YbOH and 173YbOH

“…Initial experiments were performed at ASU using a molecular beam LIF spectrometer similar to that used in previous high-resolution optical studies of 172,174 YbOH. 35,37 Briefly, YbOH is produced by laser ablating (532 nm, ~10 mJ/pulse, 20 Hz) a Yb rod in the presence of a methanol/argon supersonic expansion. The resulting beam is skimmed to produce a well collimated beam with a temporal pulse width of ~40 in the detection region.…”