Spin-aligned hydrogen (H ↑) and deuterium (D ↑) are generally predicted to be stable for $\frac{\mathcal{H}}{T}\gtrsim {10}^6$ G/K. Magnetic-field-dependent resonances (inverse to field-induced predissociations of high vibrational-rotational levels of HD and ${\mathrm{D}}_2$) provide exceptions to this general rule. Their existence suggests 50 kG (H ↑ + D ↑) and 19 kG (D ↑ + D ↑) should be avoided for stable H ↑ and D ↑. Induced predissociation observations should yield ultraprecise resonance information and dissociation limits.

• Received 12 October 1976

DOI:https://doi.org/10.1103/PhysRevLett.37.1628