The orientation state of the molecule can be described by angular momentum eigenstate of the molecule rotating around its long axis ; the state of the molecule center - of - mass can be described by energy eigenstate of the particle in the harmonic well potential )和分子质心位矢( ? ) 。分子取向态可用分子绕长轴自转角动量本征态描述；分子质心态可用质点在谐振子势阱中的能量本征态来描述。
