Evaluate, by explicit summation, the mean vibrational energy of CS₂ and plot its value as a function of temperature. At what temperature is the equipartition value within 5 per cent of the accurate value? Use the wavenumbers 658 cm⁻¹ (symmetric stretch), 397 cm⁻¹ (bend; two modes), 1535 cm⁻¹ (asymmetric stretch). The A modes are non-degenerate, E modes are doubly degenerate, and T modes are triply degenerate.