Spectroscopy, Thermochemistry, and Reactivity of Lanthanide and Actinide Molecules

The research undertaken under this grant is described in this document. The document describes progress in the construction of an instrument for recording photodissociation action spectra of mass-selected cryo-cooled cations. The instrument is not yet functional, but we anticipate trapping ions and conducting photodissociation experiments before the end of the year. It also describes resonant two-photon ionization spectra that have been recorded for uranium mononitride (UN) in the visible portion of the spectrum. These experiments are still underway at the present time. Although the spectra are a bit difficult to properly fit, due to upper state perturbations, it appears that the molecule has a ground state with {Omega} = 3.5 and a bond length of approximately 1.76 {angstrom}. Finally, results on the thermochemistry and reactivity of Th{sup +} are presented. In these studies the bond energies of the following bonds have been determined: D{sub 0}(Th{sup +}-2O) = 10.2 {+-} 0.2 eV; D0(Th{sup +}-N) = 6.69 {+-} 0.35 eV; D0(Th{sup +}-O) = 8.40 {+-} 0.28 eV; D{sub 0}(OTh{sup +}-O) = 1.8 {+-} 0.4 eV

Resonant two-photon ionization spectroscopy of jet-cooled RuC

Journal ArticleA resonant two-photon ionization study of the jet-cooled RuC molecule has identified the ground state as a 1?+ state arising from the 10?211?25rr42?4 configuration. The 3?i state arising from the 10?211?25rr42?312?1 configuration lies very low in energy, with the 3?3 and 3?2 components lying only 76 and 850 cm-1 above the ground state, respectively. Transitions from the X 1?+, 3?3 , and 3?2 states to the 3II2, 3II1, 3?3, 3?4, 1?3, and 1II1 states arising from the 10?211?25rr42?36rr1 configuration have been observed in the 12 700?18 100 cm-1 range, allowing all of these states to be placed on a common energy scale. The bond length increases as the molecule is electronically excited, from r051.608 ? in the 2?4, X 1?+ state, to 1.635 ? in the 2?312?1, 3? state, to 1.66 ? in the 2?36rr1, 3II and 3? states, to 1.667 ? in the 2?36rr1, 1? and 1.678 ? in the 2?36rr1, 1II state. A related decrease in vibrational frequency with electronic excitation is also observed. Hyperfine splitting is observed in the 2?312?1, 3?3 state for the 99Ru(I55/2)12C and 101Ru(I55/2)12C isotopic combinations. This is analyzed using known atomic hyperfine parameters to show that the 12? orbital is roughly 83% 5sRu in character, a result in good agreement with previous work on the related RhC and CoC molecules

Resonant two-photon ionization spectroscopy of jet-cooled PdC

Journal ArticleThe first optical investigation of the spectra of diatomic PdC has revealed that the ground state has ?=0+, with a bond length of r0=1.712?. The Hund?s case (a) nature of this state could not be unambiguously determined from the experimental data, but dispersed fluorescence studies to be reported in a separate publication, in combination with a comparison to theoretical calculations, demonstrate that it is the 2?4 12?2, 1?+0+ state, which undergoes spin?orbit mixing with a low-lying 2?4 12?1 6rr1, 3II0+ state. An excited 3?+ state with re=1.754?0.003? (r051.758?0.002?) and ?G1/25794 cm-1 is found at T0=17 867 cm21. Although only the ?=1 component of this state is directly observed, the large hyperfine splitting of this state for the 105Pd 12C isotopomer implies that an unpaired electron occupies an orbital that is primarily of 5s character on Pd. Comparison to ab initio calculations identifies this state as 2?4 12?113?1, 3?+1. To higher wavenumbers a number of transitions to states with ?=1+ have been observed and rotationally analyzed. Two groups of these have been organized into band systems, despite the clear presence of homogeneous perturbations between states with ?=0+ in the region between 22 000 and 26 000 cm-1

The bond energy of Rh?

Journal ArticleIn a spectroscopic investigation of jet-cooled Rh2 by the resonant two-photon ionization method, an abrupt predissociation threshold is observed in a dense set of vibronic levels at 19 405?4 cm-1. Based on the high density of states expected in the rhodium dimer, the sharp definition of the predissociation threshold that is observed, and the validation of a similar conclusion in the case of V2, it is argued that predissociation occurs as soon as the energy of the separated ground state atoms is exceeded. On this basis the bond energy of Rh2 is assigned as D0(Rh2)=19 405 ?4 cm-1=2.4059?0.0005 eV. This value is compared to the results of other experiments and to theoretical calculations. The bond energy of disilver, D0(Ag2)=1.65?0.03 eV, provides a particularly useful standard of comparison, and suggests that 4d contributions to the bond energy of Rh2 amount to at least 0.76 eV

Managing for change: October 11, 1989

Bi-weekly newsletter of University Hospital's Change Project, provided to managers at the hospital

Misdiagnosis, Mistreatment, and Harm - When Medical Care Ignores Social Forces.

The Case Studies in Social Medicine demonstrate that when physicians use only biologic or individual behavioral interventions to treat diseases that stem from or are exacerbated by social factors, we risk harming the patients we seek to serve

Accelerator performance analysis of the Fermilab Muon Campus

Fermilab is dedicated to hosting world-class experiments in search of new physics that will operate in the coming years. The Muon g-2 Experiment is one such experiment that will determine with unprecedented precision the muon anomalous magnetic moment, which offers an important test of the Standard Model. We describe in this study the accelerator facility that will deliver a muon beam to this experiment. We first present the lattice design that allows for efficient capture, transport, and delivery of polarized muon beams. We then numerically examine its performance by simulating pion production in the target, muon collection by the downstream beam line optics, as well as transport of muon polarization. We finally establish the conditions required for the safe removal of unwanted secondary particles that minimizes contamination of the final beam.Comment: 10 p

The 2016 Revision of ISO 1 – Standard Reference Temperature for the Specification of Geometrical and Dimensional Properties

This paper discusses the changes in the 2016 (third edition) of International Standard ISO 1. While the value of the standard reference temperature remains unchanged at 20 °C, the important definitions for the “reference temperature” and “standard reference temperature,” absent in prior editions, are now defined, with the latter exclusively reserved for the assignment of the internationally agreed upon temperature of 20 °C. The scope of the revised Standard has been carefully refined and made more explicit. This, together with other clarifications and improvements, has eliminated the ambiguities associated with specifications at non-standard reference temperatures and allows, if needed, different reference temperatures to be associated with different properties of a workpiece. The relationship between ISO 1 and dimensional measurements is also discussed and clarified. In this paper, we discuss the motivation for these changes and present several issues debated during the revision process for the benefit of future standards committees that might study this topic

Antiretroviral drug levels and interactions affect lipid, lipoprotein, and glucose metabolism in HIV-1 seronegative subjects: A pharmacokinetic- pharmacodynamic analysis

BACKGROUND: HIV-infected patients treated with antiretroviral medications (ARVs) develop undesirable changes in lipid and glucose metabolism that mimic the metabolic syndrome and may be proatherogenic. Antiretroviral drug levels and their interactions may contribute to these metabolic alterations. METHODS: Fifty-six HIV-seronegative adults were enrolled in an open-label, randomized, pharmacokinetic interaction study, and received a non-nucleoside reverse transcriptase inhibitor (efavirenz on days 1-21) plus a protease inhibitor (PI; amprenavir on days 11-21), with a second PI on days 15-21 (saquinavir, nelfinavir, indinavir, or ritonavir). Fasting triglycerides, total, LDL- and HDL-cholesterol, glucose, insulin and C-peptide levels were measured on days 0, 14, 21, and 2-3 weeks after discontinuing drugs. Regression models were used to estimate changes in these parameters and associations between these changes and circulating levels of study drugs. RESULTS: Short-term efavirenz and amprenavir administration significantly increased cholesterol, triglycerides and glucose levels. Addition of a second protease inhibitor further increased triglycerides, total- and LDL-cholesterol levels. Higher amprenavir levels predicted larger increases in triglycerides, total and LDL-cholesterol. Two weeks after all study drugs were stopped, total, LDL- and HDL-cholesterol remained elevated above baseline. CONCLUSIONS: ARV regimens that include a non-nucleoside reverse transcriptase inhibitor plus single or boosted PIs are becoming more common, but the pharmacodynamic interactions associated with these regimens can result in persistent, undesirable alterations in serum lipid/lipoprotein levels. Additional pharmacodynamic studies are needed to examine the metabolic effects of ritonavir-boosted regimens, with and without efavirenz

Power counting with one-pion exchange

Techniques developed for handing inverse-power-law potentials in atomic physics are applied to the tensor one-pion exchange potential to determine the regions in which it can be treated perturbatively. In S-, P- and D-waves the critical values of the relative momentum are less than or of the order of 400 MeV. The RG is then used to determine the power counting for short-range interaction in the presence of this potential. In the P-and D-waves, where there are no low-energy bound or virtual states, these interactions have half-integer RG eigenvalues and are substantially promoted relative to naive expectations. These results are independent of whether the tensor force is attractive or repulsive. In the 3S1 channel the leading term is relevant, but it is demoted by half an order compared to the counting for the effective-range expansion with only a short-range potential. The tensor force can be treated perturbatively in those F-waves and above that do not couple to P- or D-waves. The corresponding power counting is the usual one given by naive dimensional analysis.Comment: 18 pages, RevTeX (further details, explanation added