# 📐  L2 Spec — Semi-Empirical Quantum Chemistry (AM1, PM6, DFTB, xTB) Mismatch-Only Spec

**ID:** `L2-304-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-304`](/artifact/l1/L1-304)

> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.45 · **Delta tier:** 5
> **⛓ On-chain block:** 41554117

---

## 1. Domain Ω

**Type:** `range`

| Parameter | Unit | Range |
|---|---|---|
| Method | — | AM1, PM6, PM7, DFTB3, GFN1-xTB, GFN2-xTB |
| N atoms | — | 2 – 100000 |
| N basis | — | 10 – 500000 |

## 2. Tolerance (ε)

**Type:** `fn`

```
3.0 * (1 + 0.1 * mismatch_severity)
```

## 3. Difficulty

| Property | Value |
|---|---|
| Difficulty score | 0.45 |
| Delta tier | 5 |

## 4. Fingerprint

`aaf8cae25802898dc9e9ebc591f0c47338a60279fe24becb3e91a7113a034411`

## 5. On-chain Registration

- **Chain hash:** `0x35a1c9c772a69674faddc36b02ab9d27d3bf2eaf43e90b5feef21cc39c0a7170`
- **Chain tx hash:** `0xef26cc54b501637edb59690f78ad292e1ff21465bef7c8319d9d2b2d09c4fc81`
- **Chain block:** `41554117`

---

## File Mapping

This bundle consists of: `L2-304-001.md`, `L2-304-001.json`.

| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-304-001.md` | Source of truth — edit this | Human or LLM |
| `L2-304-001.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 `L2-304-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._