We show that strong molecular rotation drastically modifies the autodetachment of C_{2}^{-} ions in the lowest quartet electronic state a^{4}Σ_{u}^{+}. In the strong-rotation regime, levels of this state only decay by a process termed "rotationally assisted" autodetachment, whose theoretical description is worked out based on the nonlocal resonance model. For autodetachment linked with the exchange of six rotational quanta, the results reproduce a prominent, hitherto unexplained electron emission signal with a mean decay time near 3 ms, observed on stored C_{2}^{-} ions from a hot ion source.
View Article and Find Full Text PDFWe present a merged-beams study of reactions between HD^{+} ions, stored in the Cryogenic Storage Ring (CSR), and laser-produced ground-term C atoms. The molecular ions are stored for up to 20 s in the extreme vacuum of the CSR, where they have time to relax radiatively until they reach their vibrational ground state (within 0.5 s of storage) and rotational states with J≤3 (after 5 s).
View Article and Find Full Text PDFThe objective of this study was to investigate the variables associated with multimorbidity status among older United States (US) adults with self-reported pain and opioid use. This study used a cross-sectional retrospective database design that included US adults aged ≥50 years with self-reported pain who used an opioid in 2019 in the Medical Expenditure Panel Survey data. Multivariable logistic regression models, weighted to produce nationally representative estimates, were used to determine variables significantly associated with multimorbidity status (≥2 versus <2 chronic conditions).
View Article and Find Full Text PDFWhile the dissociative recombination (DR) of ground-state molecular ions with low-energy free electrons is generally known to be exothermic, it has been predicted to be endothermic for a class of transition-metal oxide ions. To understand this unusual case, the electron recombination of titanium oxide ions (TiO) with electrons has been experimentally investigated using the Cryogenic Storage Ring. In its low radiation field, the TiO ions relax internally to low rotational excitation (≲100 K).
View Article and Find Full Text PDFFor sensitive studies of molecular ions in electrostatic storage rings, the exact knowledge of the isobaric composition of stored beams from a variety of ion sources is essential. Conventional mass-filtering techniques are often inefficient to resolve the beam components. Here, we report the first isochronous mass spectrometry in an electrostatic storage ring, which offers a high mass resolution of Δm/m < 1 × 10 even for heavy molecular species with m > 100 u and uncooled ion beams.
View Article and Find Full Text PDFWe describe a merged beams experiment to study ion-neutral collisions at the Cryogenic Storage Ring of the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. We produce fast beams of neutral atoms in their ground term at kinetic energies between 10 and 300 keV by laser photodetachment of negative ions. The neutral atoms are injected along one of the straight sections of the storage ring, where they can react with stored molecular ions.
View Article and Find Full Text PDFThis study evaluated a pharmacist-led telephonic Medication Therapy Management (MTM) program for rural patients in Arizona with poor access to healthcare services. A pharmacist provided telephonic MTM services to eligible adult patients living in rural Arizona communities with a diagnosis of diabetes and/or hypertension. Data were collected and summarized descriptively for demographic and health conditions, clinical values, and medication-related problems (MRPs) at the initial consultation, and follow-up data collected at 1 and 3 months.
View Article and Find Full Text PDFWe present state-selected measurements of rotational cooling and excitation rates of CH^{+} molecular ions by inelastic electron collisions. The experiments are carried out at a cryogenic storage ring, making use of a monoenergetic electron beam at matched velocity in combination with state-sensitive laser dissociation of the CH^{+} ions for simultaneous monitoring of the rotational level populations. Employing storage times of up to 600 s, we create conditions where electron-induced cooling to the J=0 ground state dominates over radiative relaxation, allowing for the experimental determination of inelastic electron collision rates to benchmark state-of-the-art theoretical calculations.
View Article and Find Full Text PDFThe epoch of first star formation in the early Universe was dominated by simple atomic and molecular species consisting mainly of two elements: hydrogen and helium. Gaining insight into this constitutive era requires a thorough understanding of molecular reactivity under primordial conditions. We used a cryogenic ion storage ring combined with a merged electron beam to measure state-specific rate coefficients of dissociative recombination, a process by which electrons destroy molecular ions.
View Article and Find Full Text PDFPhotodetachment thermometry on a beam of OH^{-} in a cryogenic storage ring cooled to below 10 K is carried out using two-dimensional frequency- and time-dependent photodetachment spectroscopy over 20 min of ion storage. In equilibrium with the low-level blackbody field, we find an effective radiative temperature near 15 K with about 90% of all ions in the rotational ground state. We measure the J=1 natural lifetime (about 193 s) and determine the OH^{-} rotational transition dipole moment with 1.
View Article and Find Full Text PDFAs part of the 2016 Academic Emergency Medicine Consensus Conference, "Shared Decision Making in the Emergency Department: Development of a Policy-relevant Patient-centered Research Agenda," a panel of representatives from the Office of Emergency Care Research, the Patient-Centered Outcomes Research Institute, the American Heart Association, the John A. Hartford Foundation, and the Emergency Care Coordination Center were assembled to discuss funding opportunities for future research in this field. This article summarizes their discussion of funding priorities and examples of successfully funded projects related to shared decision making in emergency medicine.
View Article and Find Full Text PDFDiagnostic testing is an integral component of patient evaluation in the emergency department (ED). Emergency clinicians frequently use diagnostic testing to more confidently exclude "worst-case" diagnoses rather than to determine the most likely etiology for a presenting complaint. Increased utilization of diagnostic testing has not been associated with reductions in disease-related mortality but has led to increased overall healthcare costs and other unintended consequences (e.
View Article and Find Full Text PDFAn electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.
View Article and Find Full Text PDFWe have studied the photodissociation of CH^{+} in the Cryogenic Storage Ring at ambient temperatures below 10 K. Owing to the extremely high vacuum of the cryogenic environment, we were able to store CH^{+} beams with a kinetic energy of ∼60 keV for several minutes. Using a pulsed laser, we observed Feshbach-type near-threshold photodissociation resonances for the rotational levels J=0-2 of CH^{+}, exclusively.
View Article and Find Full Text PDFA compact, highly efficient single-particle counting detector for ions of keV/u kinetic energy, movable by a long-stroke mechanical translation stage, has been developed at the Max-Planck-Institut für Kernphysik (Max Planck Institute for Nuclear Physics, MPIK). Both, detector and translation mechanics, can operate at ambient temperatures down to ∼10 K and consist fully of ultra-high vacuum compatible, high-temperature bakeable, and non-magnetic materials. The set-up is designed to meet the technical demands of MPIK's Cryogenic Storage Ring.
View Article and Find Full Text PDFThe absolute configuration of (R,R)-2,3-dideuterooxirane, which has been independently determined using Coulomb explosion imaging, has been unambiguously chemically correlated with the stereochemical key reference (+)-glyceraldehyde. This puts the absolute configuration of D(+)-glyceraldehyde on firm experimental grounds.
View Article and Find Full Text PDFIn chemistry and biology, chirality, or handedness, refers to molecules that exist in two spatial configurations that are incongruent mirror images of one another. Almost all biologically active molecules are chiral, and the correct determination of their absolute configuration is essential for the understanding and the development of processes involving chiral molecules. Anomalous x-ray diffraction and vibrational optical activity measurements are broadly used to determine absolute configurations of solid or liquid samples.
View Article and Find Full Text PDFObjectives: To examine self-reported exposure to a physical activity (PA) promoting intervention and changes to school environmental PA factors.
Methods: Randomly selected 8(th) grade girls in year 2 (N = 3469) and year 3 (N = 3462) completed surveys on exposure to the health education, PE components, PA programming, and PA supporting messages. Girls' perceptions of their school-environment and an assessment of school environmental factors by principals in support of PA also were measured.
Background: We examined associations among multilevel variables and girls' physical activity to determine whether they vary at different adolescent ages.
Methods: All field sites of the Trial of Activity for Adolescent Girls contributed participants from 6th (n = 1576) and 8th grades (n = 3085). The Maryland site contributed an 11th grade sample (n = 589).
We present initial-state selective fully differential cross sections for ionization of lithium by 24 MeV O8+ impact. The data for ionization from the 2s and 2p states look qualitatively different from each other and from 1s ionization of He. For ionization from the 2p state, to which in our study the m(L)=-1 substate predominantly contributes, we observe orientational dichroism and for 2s ionization pronounced interference which we trace back to the nodal structure of the initial-state wave function.
View Article and Find Full Text PDFWe have measured fully differential cross sections for single ionization and transfer ionization (TI) in 16 MeV O(7+)+He collisions. The impact parameters mostly contributing to single ionization are about an order of magnitude larger than for TI. Therefore, the projectile beam was much more coherent for the latter compared to the former process.
View Article and Find Full Text PDFWe present a novel experimental tool allowing for kinematically complete studies of break-up processes of laser-cooled atoms. This apparatus, the 'MOTReMi,' is a combination of a magneto-optical trap (MOT) and a reaction microscope (ReMi). Operated in an ion-storage ring, the new setup enables us to study the dynamics in swift ion-atom collisions on an unprecedented level of precision and detail.
View Article and Find Full Text PDFWe present the results of a Coulomb explosion experiment that allows for the imaging of the rovibrational wave function of the metastable H2- ion. Our measurements confirm the predicted large internuclear separation of 6 a.u.
View Article and Find Full Text PDFBackground: Recruitment and retention of adolescent research participants presents unique challenges and considerations when conducting epidemiological studies.
Purpose: To describe the use of the social networking website in the re-recruitment and tracking of adolescent girls into a follow-up study of the Trial of Activity for Adolescent Girls (TAAG) at the University of Maryland field site.
Methods: 730 girls were recruited as 8th graders into TAAG.