Vibrational Spectra of Diatomic Molecules

The lowest vibrational transitions of diatomic molecules approximate the quantum harmonic oscillator and can be used to imply the bond force constants for small oscillations.

The following is a sampling of transition frequencies from the n=0 to n=1 vibrational level for diatomic molecules and the calculated force constants. Molecule 分子 Frequency x1013 Hz 频率 x10 13 Hz Force constant N/m 力常数 N/m HF 12.4* 970 HCl 8.66 480 HBr 7.68 384 HI 6.69 294 CO 6.42 1860 NO 无 5.63 1550 * From vibrational transition 4138.52 cm-1 in Herzberg's tabulation. 以下是从双原子分子n=0到n=1振动电平的跃迁频率示例以及计算出的力常数。* 从Herzberg的表格中得到的振动跃迁频率为4138.52 cm⁻¹。

These bond force constants were calculated from the vibrational frequency in the same way the force constant for HCl was calculated.