Study on high-temperature spectra of asymptotic asymmetric-top radical SiO2

Total internal partition sums are calculated in theproduct approximation at temperatures up to 6000~K for theasymptotic asymmetric-top SiO₂ molecule. The rotationalpartition function and the vibrational partition function arecalculated with the rigid-top model and in the harmonic oscillatorapproximation, respectively. Our values of the total internalpartition sums are consistent with the calculated value in theGaussian program within $-0.137$% at 296~K. Using the calculatedpartition functions and the rotationless transition dipole momentsquared as a constant, we calculate the line intensities of 001--000band of SiO₂ at normal, medium and high temperatures.Simulated spectra of the 001--000 band of the asymptotic asymmetric-topSiO₂ molecule at 2000, 5000 and 6000~K are also obtained.