| 1. Domain | 1.1 Scope of the Domain | Boundaries | The range of phenomena the science includes and excludes. | Studies the rates, pathways, and mechanisms of chemical reactions; excludes purely thermodynamic descriptions of equilibrium without regard to rate or pathway. |
| | Scale | The spatial, temporal, or organizational level at which the science operates (e.g., quantum, cellular, social, cosmic). | Operates from atomic and molecular scales (transition states, collisions) to macroscopic reaction rates in bulk systems. |
| 1.2 Ontological Commitments | Entities | The kinds of things assumed to exist within the domain (particles, organisms, agents, fields, etc.). | Reactants, products, intermediates, transition states, activated complexes, energy surfaces, colliding particles. |
| | Properties | The fundamental attributes these entities possess (mass, charge, genotype, preference, etc.). | Activation energy, rate constants, reaction cross-sections, molecular energies, orientation factors, collision frequencies. |
| | Categories | The basic ontological types used to classify domain elements (substances, processes, relations, structures). | Elementary vs. complex reactions, unimolecular/bimolecular steps, chain processes, catalytic cycles, energy-transfer events. |
| 1.3 State-Variables | Variables | The measurable or definable properties that describe system conditions. | Concentrations, rate constants, temperature, pressure, reaction progress variables, energy distributions, collisional parameters. |
| | Parameterization | How variables encode and represent the system’s state. | State descriptions encoded through rate laws, Arrhenius parameters, energy surface coordinates, and reaction-coordinate diagrams. |
| 1.4 Admissible Idealizations | Simplifications | Conceptual reductions used to make the domain tractable (point masses, rational agents, perfect gases). | Ideal-gas behavior, simple collision models, steady-state approximations, transition-state approximations, negligible back-reactions. |
| | Validity Conditions | The limits and contexts in which idealizations hold or break down. | Valid at appropriate temperature ranges, dilute limits, weak coupling, or when intermediate lifetimes justify steady-state or pre-equilibrium approximations. |
| 1.5 Domain Assumptions | Structural Assumptions | Background ontological stances such as determinism, continuity, randomness, discreteness. | Assumes definable reaction pathways, time evolution governed by differential rate laws, probabilistic collision descriptions. |
| | Implicit Commitments | Unstated but necessary assumptions that shape the field’s conceptual structure. | Assumes molecular randomness, adequate sampling of collisions, meaningful reaction coordinates, smooth energy landscapes. |
| 1.6 Internal Coherence Requirements | Consistency | The demand that domain concepts do not contradict one another. | Requires compatibility of rate laws, mechanistic steps, energy barriers, and macroscopic observables; pathways must not contradict conservation laws. |
| | Compatibility | The requirement that entities, variables, and assumptions fit together into a unified descriptive framework. | Demands alignment between kinetics, energy surfaces, molecular dynamics, and mechanistic hypotheses across all levels of description. |
| 2. Evidence Layer | 2.1 Observable Phenomena | Observables | The aspects of the domain that can produce detectable signals accessible to measurement. | Time-dependent concentration changes, reaction rates, product distributions, intermediate lifetimes, molecular scattering signals, energy transfer signatures. |
| | Detection Limits | The boundaries of what can be resolved or sensed by current instruments or methods. | Limited by temporal resolution (fast processes), concentration sensitivity, ability to detect transient intermediates, signal-to-noise in spectroscopy or kinetics measurements. |
| 2.2 Measurement Systems | Units | Standardized quantifications (meters, seconds, volts, decibels, dollars, etc.) necessary for consistent comparison. | Seconds, molarity, pressure, temperature, rate constants (s⁻¹, M⁻¹ s⁻¹), energy units (kJ/mol), cross-sections, molecular flux units. |
| | Instruments | Devices and tools (microscopes, spectrometers, sensors, surveys, detectors) used to produce measurements. | Stopped-flow reactors, flash photolysis setups, mass spectrometers, IR/UV-Vis/Raman spectroscopy, molecular-beam instruments, pump–probe lasers, high-speed detectors. |
| 2.3 Operational Definitions | Definitions | Terms defined by specific measurement procedures, ensuring empirical clarity. | Rate defined via concentration change over time; activation energy via Arrhenius analysis; intermediates defined by transient spectral or mass features. |
| | Procedures | The explicit steps required to perform a measurement in a reproducible way. | Time-resolved sampling, rapid-mixing protocols, temperature-controlled runs, laser-induced excitation, reproducible integration of spectral signals. |
| 2.4 Data Acquisition | Protocols | Formal processes for gathering data under controlled or standardized conditions. | Controlled initiation of reactions (thermal, photochemical), repeated kinetic runs, steady-state monitoring, pressure/temperature ramps, beam-collision measurements. |
| | Sampling | Rules determining which subset of the domain is measured and how representative it is. | Time-point selection for rate determination, ensemble averaging, sampling energy distributions in molecular beams, choosing representative reaction coordinates. |
| 2.5 Data Character & Format | Data Types | The form raw evidence takes (time series, spectra, images, counts, qualitative records). | Time series, rate curves, transient absorption spectra, scattering distributions, product branching ratios, molecular trajectory datasets. |
| | Resolution | The granularity or precision with which data is captured. | Determined by detector speed, spectral bandwidth, temporal pulse width, concentration precision, noise floor in fast-transient detection. |
| 2.6 Reliability & Calibration | Calibration | Adjustment procedures ensuring instruments produce accurate results. | Wavelength calibration, intensity calibration, flow-rate calibration, temperature/pressure baselining, zero-time alignment in pump–probe experiments. |
| | Error Characterization | Identification and quantification of noise, uncertainty, bias, and measurement error. | Quantifying noise, drift, baseline instability, mixing inefficiency, beam-energy uncertainties, finite time resolution, and model-fitting error in rate extraction. |
| 3. Structural Layer | 3.1 Patterns & Regularities | Laws / Relations | Stable, repeatable patterns governing how observables behave across conditions. | Rate laws, Arrhenius relation, transition-state theory rate expression, energy-transfer relations, collision-theory relations, branching patterns. |
| | Invariants | Quantities or properties that remain constant under transformations (symmetries, conservation laws). | Conservation of energy and momentum in collisions, invariant reaction coordinate ordering, symmetry restrictions on allowed pathways, invariant branching ratios in limiting cases. |
| 3.2 Causal Architecture | Mechanisms | Underlying processes or structures that produce the observed regularities. | Elementary reaction steps, collision-induced transitions, barrier crossing, energy redistribution, catalytic cycles, chain-propagation sequences. |
| | Pathways | Organized sequences of interactions forming a causal chain or network. | Reaction coordinate flow, multistep mechanisms, radical chains, catalytic loops, photochemical pathways, collisional activation and deactivation sequences. |
| 3.3 Theoretical Vocabulary | Concepts | Core terms that encode the domain’s structure (force, gene, equilibrium, field). | Transition state, activation energy, pre-exponential factor, reaction coordinate, surface crossing, collision complex, branching ratio. |
| | Classifications | Taxonomies, categories, or typologies that organize entities and relations. | Elementary vs. composite mechanisms, chain reactions, catalytic mechanisms, unimolecular/bimolecular classes, thermal vs. photochemical reactions. |
| 3.4 Formal Representations | Equations | Mathematical constructs expressing laws, relations, or mechanisms. | Arrhenius equation, Eyring equation (TST), rate laws, master equations, RRKM theory equations, Fokker–Planck formulations for energy redistribution. |
| | Models | Structured representations—mathematical, computational, or conceptual—used to predict and explain phenomena. | Transition-state theory, RRKM theory, collision theory, potential energy surface models, molecular dynamics models, master-equation kinetic models. |
| 3.5 Idealized Structures | Simplified Models | Purposeful abstractions that capture essential dynamics while omitting irrelevant detail. | Single-barrier reaction models, idealized collision models, harmonic transition-state approximations, steady-state approximations in multistep kinetics. |
| | Limit Conditions | Regimes where specific models or approximations hold (classical vs. quantum, linear vs. nonlinear). | Breakdown at strong-coupling, non-statistical dynamics, ultrafast processes, strong anharmonicity, or systems lacking separable reaction coordinates. |
| 3.6 Integrative Frameworks | Unifying Theories | Higher-order structures that connect disparate laws or mechanisms under a coherent whole. | Integration of microscopic dynamics with macroscopic rate laws; unified barrier-crossing theories; connection of kinetics to thermodynamics and statistical mechanics. |
| | Interdisciplinary Links | Points where the theory connects to adjacent sciences or larger explanatory systems. | Links to catalysis, atmospheric chemistry, combustion, materials kinetics, quantum dynamics, photochemistry, and biochemical reaction networks. |
| 4. Method Layer | 4.1 Inquiry Design | Experimental Design | Structured plans for manipulating variables to test causal claims. | Controlling temperature, pressure, concentration, photonic excitation, or collision energy to probe rate laws, intermediates, and reaction pathways. |
| | Observational Design | Systematic approaches for gathering non-manipulated data (surveys, field studies, natural experiments). | Recording spontaneous reaction progress, natural decay or growth of species, scattering distributions, and relaxation dynamics without intentional perturbation. |
| 4.2 Testing & Validation | Hypothesis Testing | Procedures for evaluating whether evidence supports or contradicts specific claims. | Comparing measured rate laws, activation energies, branching ratios, or molecular beam scattering data with predicted mechanistic models. |
| | Replication | The requirement that results be independently reproducible under similar conditions. | Reproducing kinetic runs, time-resolved spectra, transient intermediate detection, and molecular-beam collision outcomes across instruments and laboratories. |
| 4.3 Inference & Evaluation | Statistical Inference | Rules for drawing conclusions from noisy or incomplete data. | Extracting rate constants from noisy time-series, fitting Arrhenius plots, estimating activation parameters, analyzing product distributions and decay functions. |
| | Model Comparison | Criteria (fit, simplicity, predictive accuracy, robustness) used to evaluate competing models. | Evaluating collision-theory, RRKM, TST, or mechanistic models on goodness-of-fit, predictive accuracy, and physical plausibility. |
| 4.4 Error Management | Error Analysis | Identification and quantification of random and systematic errors. | Quantifying uncertainties from timing resolution, mixing efficiency, spectral overlap, detector limits, baseline drift, and fitting error in rate extraction. |
| | Bias Control | Methods for minimizing subjective, instrumental, or procedural biases. | Ensuring unbiased sampling, verifying reproducibility of excitation pulses, randomizing initial conditions, controlling for photolysis artifacts or beam inhomogeneity. |
| 4.5 Adjudication & Revision | Peer Scrutiny | Collective evaluation of claims through critique, review, and debate. | Independent evaluation of mechanistic proposals, kinetic data processing, rate extraction methods, and interpretation of scattering or transient spectra. |
| | Theory Revision | Procedures for modifying, replacing, or discarding models based on new evidence. | Updating mechanisms, rate expressions, potential energy surfaces, or branching assumptions when discrepancies arise with measured or simulated dynamics. |
| 4.6 Integrity Conditions | Transparency | Requirements to disclose methods, data, assumptions, and limitations. | Full reporting of concentrations, pulse energies, calibration parameters, assumptions, models used, fitting procedures, and uncertainty characterization. |
| | Ethical Standards | Norms ensuring responsible conduct in experimentation, data handling, and publication. | Ensuring reproducibility, responsible data treatment, accurate uncertainty reporting, and honest representation of mechanistic evidence. |