Nitric oxide, NO

PHYSICS · Multi-part · Fermi University Physics · Atomic, Molecular & Optical Physics · Molecular structure and spectra · Molecular structure and spectra

Reading the Spectrum, Ch Two nuclei on one curve: rotation, vibration and the spectrum of a diatomic molecule

Problem

Nitric oxide, NO, has its first strong electronic absorption near

226\,\mathrm{nm}

, a vibrational constant

\omega_e = 1904.2\,\mathrm{cm^{-1}}

, and a rotational constant

B_e = 1.705\,\mathrm{cm^{-1}}

. The atomic masses are

m_{\rm N}=14.003\,\mathrm{u}

and

m_{\rm O}=15.999\,\mathrm{u}

. ((a)) Convert each of the three quantities above to an energy in eV, and state which region of the electromagnetic spectrum (ultraviolet, infrared, or far infrared/microwave) each falls in. ((b)) Find the reduced mass

\mu

of NO, the ratio

\mu/m_e

, and the mass-ratio estimate

\sqrt{\mu/m_e}

for the factor separating one energy scale from the next. ((c)) Compare this predicted factor with the two actual ratios from part (a) (electronic/vibrational and vibrational/rotational), and comment on how well the simple mass-ratio estimate works.

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