Tongmei Ma

The permanent electric dipole moments and magnetic g factors of uranium monoxide

Permanent electric dipole moments and magnetic g factors for uranium monoxide (UO) have been determined from analyses of optical Stark and Zeeman spectra recorded at a spectral resolution that approaches the natural linewidth limit. Numerous branch features in the previously characterized [L. A. Kaledin et al., J. Mol. Spectrosc. 164, 27 (1994)] (0,0) [18403]5-X(1)4 and (0,0) [18404]5-X(1)4 electronic transitions were recorded in the presence of tunable static electric (Stark effect) or magnetic (Zeeman effect) fields. The lines exhibited unusually large Zeeman tuning effects. A ligand field model and an ab initio electronic structure calculation [R. Tyagi, Ph.D. thesis, The Ohio State University (2005)] were used to interpret the ground state properties. The results indicate that the low energy electronic states of UO are sufficiently ionic for the meaningful application of ligand field theory models. The dipole moments and g factors were distinctly different for the three electronic states examined, which implies that these properties may be used to deduce the underlying electronic state configurations.

High resolution laser induced fluorescence spectroscopy of the [18.8]Φi3−XΦi3 (0,0) band of cobalt monofluoride

The fine and hyperfine interaction parameters in the [18.8]Φ3 (υ=0) and XΦ3 (υ=0) states of cobalt monofluoride, CoF, have been determined from an analysis of high-resolution laser induced fluorescence spectra of the [18.8]Φ33−XΦ33 and [18.8]Φ43−XΦ43 band systems. The previously reported pure rotational transitions of the XΦ43(υ=0) state [T. Okabayashi and M. Tanimoto, J. Mol. Spectrosc. 221, 149 (2003)] were included in the data set. The hyperfine parameters for Co59 (I=7∕2) and F19 (I=1∕2) have been interpreted using atomic data together with a proposed molecular orbital description for the [18.8]Φi3 and XΦi3 states. A comparison of the hyperfine parameters in the XΦ3 state of cobalt monohydride, CoH, with those of the XΦ3 state of CoF reveals that the bonding in the two molecules is significantly different. It is shown that, in a situation where the Ω substates of a multiplet degenerate electronic state are analyzed separately, the Fermi contact parameter b can be determined with fair accuracy from the...

The hyperfine interaction in the AΠ1∕22 and XΣ+2 states of ytterbium monofluoride

The fine and hyperfine interaction parameters in the AΠ1∕22(v=0) and XΣ+2(v=0) states of the odd metal nuclear spin isotopologues of ytterbium monofluoride, Yb171F and Yb173F, have been determined from an analysis of high-resolution laser induced fluorescence spectra of the AΠ1∕22←XΣ+2(0,0) band. The observed ground XΣ+2(v=0) state Yb171(I=1∕2) Fermi contact parameter is significantly smaller than that determined from the matrix isolation electron spin resonance measurement [Van Zee et al., J. Phys. Chem. 82, 1192 (1978)]. An interpretation of the Yb173,171 magnetic hyperfine and nuclear electric quadrupole coupling parameters is given.

Optical Zeeman Spectroscopy of Ytterbium Monofluoride, YbF

The Zeeman-induced shifts and splittings of low-J lines in the (O)P(12) branch of the (0,0) band of the A(2)Pi(1/2)-X(2)Sigma(+) electronic transition of a cold molecular beam sample of ytterbium monofluoride, YbF, have been recorded. The Zeeman spectra for the (171)YbF, (172)YbF, and (174)YbF isotopologues have been analyzed using a standard effective Hamiltonian approach. The magnetic g-factors determined for the A(2)Pi(1/2)(v = 0) state are rationalized using the predicted and observed electronic state distribution. The observed Zeeman tuning of the levels in the A(2)Pi(1/2)(v = 0) state is unexpectedly large; this is caused by mixing with the B(2)Sigma(+) state.

The permanent electric dipole moment and hyperfine interaction in ruthenium monoflouride (RuF)

Ruthenium monofluoride, RuF, has been detected using low-resolution laser-induced fluorescence (LIF) in the visible and near infrared spectral regions. A visible band, designated as [18.2]5.5-X 4Phi(9/2), has been recorded field-free and in the presence of a static electric field using high-resolution LIF spectroscopy. The r0 internuclear distances for the [18.2]5.5 and X 4Phi(9/2) states were determined to be 1.911 and 1.916 A, respectively. The vibrational interval DeltaG(1/2) of 534(15) cm-1 for the X 4Phi(9/2) state was determined from the analysis of the dispersed LIF. The Stark shifts of the visible band were analyzed to produce permanent electric dipole moments of 1.97(8) and 5.34(7) D for the [18.2]5.5 and X 4Phi(9/2), states, respectively. The fluorine magnetic hyperfine structure associated with spectral features was analyzed. The hyperfine structure and dipole moments are interpreted using a molecular-orbital correlation model and compared with FeF and other ruthenium-containing molecules.

The permanent electric dipole moments and magnetic ge-factors of praseodymium monoxide (PrO)

The R(4.5) and P(6.5) branch features of the XX (0, 0) band of praseodymium monoxide (PrO) have been studied at a resolution of approximately 50 MHz field free and in the presence of static electric and magnetic fields. The permanent electric dipole moments, mu(el), of 3.01(6) D and 4.72(5) D for the X(2) (Omega = 4.5) and [18.1] (Omega = 5.5) states, respectively, were determined from the analysis of the Stark spectra. The magnetic g(e)-factors of 4.48(8) and 5.73(6) for the X(2) (Omega = 4.5) and [18.1] (Omega = 5.5) states, respectively, were determined from the analysis of the Zeeman spectra. The g(e)-factors are compared with those computed using wave functions predicted from ligand field theory and ab initio calculations. The mu(el) value for the X(2) (Omega = 4.5) state is compared to ab initio and density functional predicted values and with the experimental values of other lanthanide monoxides.

Detection of the Thorium Dimer via Two-Dimensional Fluorescence Spectroscopy

Thorium dimer, Th2, has been detected in the gas phase via two-dimensional laser-induced fluorescence electronic spectroscopy. The visible excitation spectra are broad, unstructured features with an approximate line width of 10 cm(-1). The spectrum consists of vibrational progressions associated with excitation from the ground electronic state to two different excited electronic states. The dispersed fluorescence was analyzed to give ground state vibrational constants ωe = 134.86 ± 0.66 cm(-1) and ωexe = 0.50 ± 0.04 cm(-1). Vibrational constants ωe = 169 ± 3 and 212 ± 2 cm(-1) were determined for the two excited electronic states. The radiative lifetimes were measured. A comparison with theoretical predictions is given.

Molecular beam optical Stark study of rhodium mononitride

The optical Stark effect in the Q(1) and R(0) lines of the [15.1]1-X (1)Sigma+ (1,0) band of rhodium mononitride (RhN) were recorded and analyzed to determine the permanent electric dipole moments mu for the X (1)Sigma+(upsilon=0) and [15.1]1(upsilon=1) states to be 2.43(5) and 1.75(1) D, respectively. The determined dipole moments are compared to predicted values obtained from density functional theory [Stevens et al., Chem. Phys. Lett. 421, 281 (2006)] and an all-electron ab initio calculation [Shim et al., J. Mol. Struct. THEOCHEM 393, 127 (1997)]. A simple single configuration molecular orbital correlation diagram is used to rationalize the relative values of mu for the 4d mononitrides and RhO. An electronic configuration for the [15.1]1 state is proposed based on the interpretation of the (103)Rh and (14)N magnetic hyperfine interactions.

A molecular beam optical Stark study of the [15.8] and [16.0] Π1∕22-XΣ−4 (0,0) band systems of rhodium monoxide, RhO

The R11S(0) and R11S(1) branch features of the [15.8] and [16.0]Π1∕22-XΣ−4 (0,0) subband systems of rhodium monoxide, RhO, have been studied at near the natural linewidth limit of resolution by optical Stark spectroscopy using laser induced fluorescence detection. The Stark shifts and splittings were analyzed to produce the magnitude of the permanent electric dipole moment, ∣μ∣, of 3.81(2)D for the XΣ3∕2−4 (v=0) state. The results are compared to density functional theory calculations. Trends in observed values of ∣μ∣ across the 4d series of transition metal monoxides are interpreted in terms of simple single configuration molecular orbital correlation diagrams.

Molecular beam optical Stark study of the [18.1]Π1∕22-XΣ1∕2−4 band system of rhodium monosulfide

The optical Stark effect in the R13R(0.5) branch feature of the [18.1]Π1∕22-XΣ1∕2−4 (v′,v″=0) band of rhodium monosulfide (RhS) has been recorded and analyzed to determine the permanent electric dipole moment μe of 3.40(2)D for the ground XΣ1∕2−4 (v=0) state and an upper limit of 1.5D for the [18.1]Π1∕22 state. Molecular orbital correlation diagrams are used to interpret the relative values of μe for RhN, RhO, and RhS. The Rh103(I=1∕2) magnetic hyperfine interaction in the XΣ1∕2−4 and [18.1]Π1∕22 states is analyzed.