What SPARK does

SPARK turns one or more cyclic voltammograms into a calibrated posterior over a continuous space of reaction mechanisms. A single amortized neural model returns a joint posterior over a 42-dimensional reaction-network parameter vector in milliseconds; mechanism identity is read post-hoc from which elementary-step "gates" the posterior places above kinetic silence. There is no discrete classifier and no per-mechanism refitting.

Why a posterior over mechanisms

A voltammogram often does not determine a unique mechanism. Because SPARK's posterior spans the whole manifold, it surfaces the alternative mechanisms the data genuinely admit and how strongly — something a single point fit (DigiElch / gradient fitting), handed one assumed mechanism, cannot discover. Use the mechanism selector to reconstruct each candidate and compare its fit and parameter posterior.

Elementary steps covered

Built on a unified Marcus-Hush-Chidsey / Butler-Volmer / Nernst electron-transfer law: plain electron transfer (E), following chemical reaction (EC), second electron transfer (ECE), disproportionation (DISP), catalytic regeneration (EC'), preceding equilibrium (CE), two-electron (EE), radical-radical dimerization, radical-substrate coupling, proton-coupled electron transfer (PCET), surface adsorption (Laviron), plus the double-layer capacitance.

How to use

Upload potentiostat CSVs (one per scan rate; columns: potential in V, current in A/mA/µA, and optionally time in s to auto-detect the scan rate) or plot images. Enter scan rates and, if known, the formal potential and cell parameters for accurate nondimensionalization. Then pick a mechanism to reconstruct and inspect its parameter posterior.

Model

Continuous-manifold simulation-based inference (calibrated RQ-NSF density estimator) trained on a coupled reaction-diffusion-adsorption voltammetry simulator. Outer-sphere electron transfer.