Optically detected gas phase magnetic resonance spectrum of the CN radical

Abstract

The microwave magnetic resonance spectrum of rotationally perturbed levels of the ${\mathrm{A\hspace{0.17em}}}^2{\Pi }_{\text{3/2}}$ and B² Σ⁺ excited electronic states of the CN radical has been observed in the gas phase using optical detection. The theory of the Zeeman effect has been used to calculate the energy levels of the system as a function of applied magnetic field strength. The parameters appearing in the molecular Hamiltonian have been adjusted to produce agreement between the experimental and calculated spectrum, and this fitting procedure has provided measured values for the interelectronic state coupling parameters and certain other molecular constants. The values of these interelectronic coupling parameters between the ν = 0, B² Σ⁺ state and the ${\text{ν = 10,\hspace{0.17em}A\hspace{0.17em}}}^2\Pi$ state were determined to be ${\text{<ν = 10\hspace{0.17em}A\hspace{0.17em}}}^2{\mathrm{\Pi |L}}_x{\text{|ν = 0B\hspace{0.17em}}}^2{\Sigma }^{+}{\text{>= 0.0038,\hspace{0.17em}<ν = 10\hspace{0.17em}A\hspace{0.17em}}}^2{\mathrm{\Pi |AL}}_x{\text{|ν = 0B\hspace{0.17em}}}^2{\Sigma }^{+}\text{>= −2602\hspace{0.17em}}\mathrm{MHz}{\text{,\hspace{0.17em}<ν = 10\hspace{0.17em}A\hspace{0.17em}}}^2{\mathrm{\Pi |BL}}_x{\text{|ν = 0B\hspace{0.17em}}}^2{\Sigma }^{+}\text{> 534\hspace{0.17em}}\mathrm{MHz}$ . These values differ from those which were calculated using optical data.