Fermi Resonance · When Two Vibrations Trade Identities
unseel.com · CO₂ dyad · ν₁ vs 2ν₂ · intensity borrowing
gap δ large
coupling W ≈50 cm⁻¹
mixing 0 / 100
step
ν₁ symmetric stretch (bright)
2ν₂ bend overtone (dark)
coupling W (cubic k₁₂₂)
observed Fermi dyad
Unseel.com · Fermi Resonance Unseel.com · Fermi Resonance — Concepts