# ⚛  L1 Principle — Reactive Molecular Dynamics (ReaxFF + Bond Order)

**ID:** `L1-307` · **Status:** ⊙ Testnet (genesis catalog)

> **🌐 Domain:** Computational Chemistry — *Bond-breaking / forming in MD*
> **🎯 Problem class:** nonlinear inverse · **🧮 Solution space:** reactive trajectory
> **📡 Carrier:** none · **🌫 Noise:** thermal langevin
> **⚖ Difficulty (δ):** 5 · **⛓ Block:** 41554115

---

## 🧠 1. Introduction

**Reactive Molecular Dynamics (ReaxFF + Bond Order)** is a **nonlinear inverse problem** whose unknown lives in **reactive trajectory** space, within the **Bond-breaking / forming in MD** sub-domain of **Computational Chemistry**.

Measurements consist of none via a **bond forming events** sensing mechanism.

The forward operator applies, in order: E · bond order operator; E · reaxff operator; time evolution of the state; O · reaction trace operator.

Observations are corrupted by Langevin-type thermal fluctuations. Well-posed forward; parameterization transfer limited.

## ⚙ 2. Forward Model

Physical chain: **x** → E · bond order → E · reaxff → Time derivative → O · reaction trace → **y** (detector).

```
y = `O.reaction_trace` ∂_t `E.reaxff` `E.bond_order` x
```

**Measurement DAG:**

| Primitive | What it does |
|---|---|
| `E.bond_order` | E · bond order operator |
| `E.reaxff` | E · reaxff operator |
| `D.time` | Time evolution of the state |
| `O.reaction_trace` | O · reaction trace operator |

## 🔬 3. Physics Fingerprint

| Property | Value |
|---|---|
| Domain | Computational Chemistry |
| Sub domain | Bond-breaking / forming in MD |
| Carrier | none |
| Problem class | nonlinear_inverse |
| Solution space | reactive_trajectory |
| Noise model | thermal_langevin |
| Integration axis | time |
| Difficulty delta | 5 |
| L dag | 3.5 |

## 📡 4. Measurement Model

Well-posed forward; parameterization transfer limited.

| Metric | Value |
|---|---|
| Metric | reaction_rate_log_error |
| Secondary | product_yield_error |

## 📏 5. Operating Range (Ω)

**Center problem class:** `reactive_md` · **Forward operator:** `reactive_md_forward`

**Center point:**

| Parameter | Unit | Value |
|---|---|---|
| Ff | — | ReaxFF_2008 |
| T k | — | 2000 |
| Dt fs | — | 0.1 |
| N atoms | — | 1000 |
| N steps | — | 1e+06 |

**Allowed bounds:**

| Parameter | Unit | Range |
|---|---|---|
| Ff | — | ReaxFF_2008, ReaxFF_CHO, ReaxFF_metal |
| T k | — | 300 – 5000 |
| Dt fs | — | 0.05 – 0.5 |
| N atoms | — | 10 – 1000000.0 |
| N steps | — | 10000 – 1000000000.0 |

## 🎯 6. Tolerance (ε)

**Center tolerance:** log10(k_rxn) <= 0.1

| Metric | Range |
|---|---|
| Reaction rate log error | 0.05 – 1.5 |

## ⚖ 7. Hardness Function

Hardness scales as **`epsilon_fn`** on **reaction_rate_log_error**, with κ = `400` and δ = `5`.

## 💾 8. Reference Dataset

- **primary** · weight 1.0 · IPFS _(not pinned yet)_

## 9. On-chain Registration

- **Chain hash:** `0x989853909bb74ad64fe76ba8589a70665eac2dc33ed62007745045e210ae6137`
- **Chain tx hash:** `0x37cbbb34943d2e5b1081a97266ff37cfb350ac25024e55f6a85504d4d9488d2b`
- **Chain block:** `41554115`

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## File Mapping

This bundle consists of: `L1-307.md`, `L1-307.json`.

| File | Role | How to regenerate |
|------|------|-------------------|
| `L1-307.md` | Source of truth — edit this | Human or LLM |
| `L1-307.json` | Structured metadata for the registry | LLM regenerates from the sections above |

**Prompt for your LLM after editing this Markdown:**

> Read the attached Markdown. Regenerate the sibling `.json` so every field matches.
> Preserve the schema documented in the rows above.
> Output each file in its own fenced code block tagged with the filename.
> Output only the JSON object.

_This Markdown was auto-synthesized from the catalog row for `L1-307`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._