Bibliographic record
Abstract
This thesis presents investigations concernig reactions of the hydroxyl radical (OH) with the reagents acetylene, ethene, benzene, ethylester of alanine and N,N-dimethylformamide in the temperature range between 60K - 300K. The reactions of acetaldehyde and N,N-dimethylformamide are furthermore investigated in presence of low quantities of water vapour. The study represents a series of reaction with rising molecular complexity. The investigations in presence of water vapour are also considered a conceptional extension of the investigation in the past.the rate constants of the OH-reactions except the one with acetylene are characterized by a negative temperature dependence. The temperature dependencies of these reactions are attributed to the barrier heights of the corresponding minimum energy pathways relative to the reactants, long range interactions between the reactants and weakly bound complexes of the reaction partners.The numerical values of the reaction rates lie in the range of 10-12 cm3s-1 for acetylene and in the order of magnitude of 10-11 cm3s-1 to 10-10 cm3s-1 for the other reactions. In the case of acetylene and ethene vibrational relaxation rates of OH v=1 are used to determine the high pressure rate constants.The reaction of acetaldehyde shows an increase of the reaction rate in presence of low quantities of water vapour. Together with theoretical Considerations of characteristic points on the potential hypersurface of the reaction the experimental findings can be tracked down to the existence of weakly bound complexes between the reaction partners. This is a matter of a catalytic effect evoked by single water molecules.Expansions through different laval nozzles are implemented to establish the low temperatures down to 60K. Nitrogen serves as the carrier gas for the kinetic experiments. Mach number, temperature and density are constant in the post nozzle flow. Hydroxyl radicals are generated via photodissociation of hydrogen peroxide at wavelengths of 193nm respectively 248nm. The temporal developement of the hydroxyl radical concentration beside an excess of the reaction partner is monitored via laser induced fluorescence.In addition to the reactions of the OH radical investigation concerning the vibrational energy transfer between the model system toluene and the bath gases helium, nitrogen and carbondioxide are presented.Highly vibrationally exited toluene molecules are generated by the isomerisation of cylcoheptatiene after photoexitation at 248nm. The temporal evolvement of toluene is probed via laser induced fluorescence with excitation wavelengths around 267nm.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".