<p>➀ Scientists achieved the first spectroscopic observation of hydrogen (H₂) and deuterium (D₂) molecules confined in atomic-scale picocavities using advanced tip-enhanced Raman spectroscopy (TERS);</p><p>➁ Quantum mechanical effects, such as nuclear delocalization, were identified as the cause of distinct vibrational responses between H₂ and D₂, revealing isotope-specific behavior not detectable by conventional methods;</p><p>➂ The findings offer new insights for energy storage systems, catalytic surfaces, and single-molecule quantum control technologies.</p>