Saturated laser induced fluorescence is used for the sensitive detection of radicals in high pressure gases. The method and its application to a series of addition reactions of HO radicals in the high pressure regime are described. Experiments between 1 and 150 bar of the bath gas He allow for falloff extrapolations to the high pressure limit of the recombination reactions. Limiting rate constants (in cm3 molecule−1 s−1) of 2.2×10−11 for HO+HO→H2O2, of 3.3×10−11 for HO+NO→HONO, of 7.5×10−11 for HO+NO2→HONO2, and of 9.7×10−13 for HO+CO→HOCO (and H+CO2) are derived at 298 K.

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Time-resolved infrared-ultraviolet double resonance (IR-UV DR) spectroscopy is used to prepare acetylene molecules (C 2 H 2 ) in specific rovibrational states of the 12 700 cm -1 4ν CH manifold of the electronic groundstate ˜, monitoring their direct excitation and collision-induced state-to-state energy transfer, by probing at ∼299 or ∼296 nm with laser-induced fluorescence via the Α electronic state. The 4ν CH manifold derives much of its IR brightness from the (ν 1 + 3ν 3 ) combination band, such that many of the rotational levels J monitored by IR-UV DR are derived from the (1 0 3 0 0) 0 vibrational state. The 4ν CH manifold of C 2 H 2 is congested and affected by anharmonic, l-resonance, and Coriolis couplings that cause other IR-dark, UVbright rovibrational levels to attain appreciable IR-UV DR intensity and to add to the complexity of intramolecular dynamics in that manifold. Consequently, collision-induced rovibrational satellites observed by IR-UV DR comprise not only regular even-∆J features but also supposedly forbidden odd-∆J features, of which the energy-transfer channel from J ) 12 to J ) 1 is particularly efficient. This paper focuses on low-J rovibrational levels of the 4ν CH manifold, particularly those with J ) 0 and J ) 1 in view of their anomalously large Stark effects that are likely to make them susceptible to collision-induced rovibrational mixing. Three complementary forms of IR-UV DR experiment are reported: IR-scanned, UV-scanned, and kinetic. These indicate that strong IR-UV DR signals observed by probing the (1 0 3 0 0) 0 J ) 0 rovibrational level are complicated by underlying IR-dark, UV-bright states, making J ) 0 unsuitable for systematic IR-UV DR studies. The (1 0 3 0 0) 0 J ) 1 rovibrational level is more amenable to unambiguous characterization and yields insight concerning even-and odd-∆J collision-induced rovibrational energy transfer and associated mechanisms.

Collision-induced state-to-state molecular energy transfer between rovibrational states in the 12,700 cm(-1) 4nu(CH) manifold of the electronic ground state X of acetylene (C(2)H(2)) is monitored by time-resolved infrared-ultraviolet double resonance (IR-UV DR) spectroscopy. Rotational J-states associated with the (nu(1) + 3nu(3)) or (1 0 3 0 0)(0) vibrational combination level, initially prepared by an IR pulse, are probed at approximately 299, approximately 296, or approximately 323 nm with UV laser-induced fluorescence via the Alpha electronic state. The rovibrational J-states of interest belong to a congested manifold that is affected by anharmonic, l-resonance, and Coriolis couplings, yielding complex intramolecular dynamics. Consequently, collision-induced rovibrational satellites observed by IR-UV DR comprise not only regular even-DeltaJ features but also supposedly forbidden odd-DeltaJ features. A preceding paper (J. Phys. Chem. A 2003, 107, 10759) focused on low-J-value rovibrational levels of the 4nu(CH) manifold (particularly those with J = 0 and J = 1) whereas this paper examines locally perturbed states at higher values of J (particularly J = 17 and 18, which display anomalous doublet structure in IR-absorption spectra). Three complementary forms of IR-UV DR experiments (IR-scanned, UV-scanned, and kinetic) are used to address the extent to which intramolecular perturbations influence the efficiency of J-resolved collision-induced energy transfer with both even and odd DeltaJ.

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Time-resolved infrared-ultraviolet double resonance (IR-UV DR) spectroscopy is used to study the kinetics of collision-induced state-to-state molecular energy transfer between rovibrational states in the 12700-cm−1 4νCH manifold of the electronic ground state of acetylene (C2H2). Particular initial and final rovibrational J-states are prepared and monitored by a pair of tunable laser pulses (IR PUMP and UV PROBE) and the kinetic results recorded by continuously varying the time delay between those pulses at a set sample pressure. After allowing for collision-induced quenching of fluorescence and mass transfer from the IR-UV optical excitation zone (by beam flyout and diffusion), an array of kinetic data for J-resolved energy-transfer channels can be interpreted by means of a mechanistically structured master-equation model. This paper focuses on kinetics derived by probing C2H2 in its 4νCH J = 12 state (which is affected by intramolecular perturbations and implicated in unusual collision-induced quasi-continuous background effects) and J-resolved collision-induced rovibrational energy transfer with both even ΔJ and (supposedly forbidden) odd ΔJ.

Background: Targeted client communication (TCC) using text messages can inform, motivate and remind pregnant and postpartum women of timely utilization of care. The mixed results of the effectiveness of TCC interventions points to the importance of theory based interventions that are co-design with users. The aim of this paper is to describe the planning, development, and evaluation of a theory led TCC intervention, tailored to pregnant and postpartum women and automated from the Palestinian electronic maternal and child health registry. Methods: We used the Health Belief Model to develop interview guides to explore women's perceptions of antenatal care (ANC), with a focus on high-risk pregnancy conditions (anemia, hypertensive disorders in pregnancy, gestational diabetes mellitus, and fetal growth restriction), and untimely ANC attendance, issues predefined by a national expert panel as being of high interest. We performed 18 in-depth interviews with women, and eight with healthcare providers in public primary healthcare clinics in the West Bank and Gaza. Grounding on the results of the in-depth interviews, we used concepts from the Model of Actionable Feedback, social nudging and Enhanced Active Choice to compose the TCC content to be sent as text messages. We assessed the acceptability and understandability of the draft text messages through unstructured interviews with local health promotion experts, healthcare providers, and pregnant women. Results: We found low awareness of the importance of timely attendance to ANC, and the benefits of ANC for pregnancy outcomes. We identified knowledge gaps and beliefs in the domains of low awareness of susceptibility to, and severity of, anemia, hypertension, and diabetes complications in pregnancy. To increase the utilization of ANC and bridge the identified gaps, we iteratively composed actionable text messages with users, using recommended message framing models. We developed algorithms to trigger tailored text messages with higher intensity for women with a higher risk profile documented in the electronic health registry.