Time resolved, subpicosecond resolution measurements of photoinitiated NO2 unimolecular decomposition rates are reported for expansion cooled and room temperature samples. The molecules are excited by 375-402 nm tunable subpicosecond pulses having bandwidths 220 cm-' to levels which are known to be thorough admixtures of the 2B2 electronically excited state and the 2A1 ground electronic state. Subsequent decomposition is probed by a 226 nm subpicosecond pulse that excites laser-induced fluorescence (LIF) in the NO product. When increasing the amount of excitation over the dissociation threshold, an uneven, "step-like" increase of the decomposition rate vs energy is observed for expansion cooled samples. The steps are spaced by-100 cm-' and can be assigned ad hoc to bending at the transition state. Relying on experimental estimates for the near threshold density of states, we point out that simple transition state theory predictions give rates that are consistent with these measured values. The rates are sufficiently rapid to question the assumption of rapid intramolecular vibrational redistribution, which is implicit in transition state theories. In contrast to expansion cooled samples, room temperature samples exhibit a smooth variation of the reaction rate vs photon energy. By comparing rates for rotationally cold and room temperature NOZ, the ON-O bond is estimated to be-40% longer in the transition state than in the parent molecule.

The monitoring and control of bioprocesses is of the utmost importance in order to provide a consistent, safe, and high-quality product for consumers. Current monitoring and control schemes rely on infrequent and time consuming offline sampling methods, which inherently leads to some variability in the process which may impact the product quality profile. As part of Lonza's dedication to process analytical technology (PAT) initiatives this study evaluated the ability to generate generic calibration models, which are independent of the cell line, using Raman probes to monitor changes in glucose, lactate, glutamate, ammonium, viable cell concentration (VCC), total cell concentration (TCC) and product concentration. Calibration models were developed from cell culture using two different CHOK1SV GS-KO cell lines producing different monoclonal antibodies (mAbs). Developed predictive models, measured changes in glucose, lactate, ammonium, VCC, and TCC with average prediction errors of 0.44, 0.23, 0.03 g L , 1.90 × 10 cells mL , and 1.85 × 10 cells mL , respectively over the course of cell culture with minimal cell line dependence. The development of these generic models allows the application of spectroscopic PAT techniques in clinical and commercial manufacturing environments, where processes are typically run once or twice in GMP manufacturing based on a common platform process. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:730-737, 2018.

Theoretical stabilization and scattering studies of resonances in the addition reaction H+CO = HCO J. Chem. Phys. 94, 4192 (1991); 10.1063/1.460652 Photoinitiated H+CO2→OH+CO reactions: OH distributions and threebody interactions in CO2H2S complexesTime resolved studies of the title reaction have been carried out by photodissociating the HI moiety within weakly bound CO 2 -HI complexes. The HOCOt intermediate decomposes via a unimolecular decomposition mechanism, and the emerging hydroxyl radicals are monitored with subpicosecond temporal resolution by using laser-induced fluorescence. The measured rates are in good agreement with several theoretical predictions: Rice, Ramsperger, Kassel, and Marcus (RRKM) calculations; classical trajectory simulations on the best available potential energy surface; and recent quantum scattering calculations.

Build-up times for the OH product of photoinduced reactions in C0,-HI complexes were measured for the photolysis wavelength range 235263 nm by using the subpicosecond resolution pump-probe method pioneered by Zewail and co-workers. There is reasonable accord with.theory and recent results from crossed-molecularbeams experiments. To illustrate the squeezed-atom effect, complementary measurements of hydrogen atom translational-energy distributions were carried out by using the high resolution high-n Rydberg time-of-flight (HRTOF) method of Welge and co-workers. Prototypical cases of Ar-HBr and Ar-HI complexes are reported.The former illustrates the squeezed-atom effect or caging of the exiting hydrogen. The latter is dominated by the formation of radical-molecule complexes. Extensions to other radical-molecule complexes are discussed.

No abstract