作为化竞党量子力学真心无力。。分子轨道无法理解。为什么成键是波函数相加反键是相减？电子云密度是平方？可否把反键轨道理解为与成键的电子对相反的区域？求大神解答o(╯□╰)o

TAT竞赛能考这么深？

挽尊，我不太清楚化学方面，所以有错误请多指教。
不论是成键轨道还是反键轨道均是波函数相加。
概率是振幅的平方。
Therefore, each energy level of the isolated atoms splits into two molecular orbitals belonging to the pair, one lower in energy than the original atomic level and one higher. For example, the ground state energy level, 1s, splits into two molecular orbitals. Since the lower orbital is lower in energy than the original atomic orbitals of the separate atoms, it is more stable, and promotes the bonding of the two H atoms into H2. This is the bonding orbital. The higher orbital is higher in energy than the original atomic orbitals and is less stable, and therefore opposes the bonding. This is the antibonding orbital. In a molecule such as H2, the two electrons normally occupy the bonding orbital, since it is lower in energy, and therefore the molecule is more stable than the separate H atoms.
以上来自维基
对于最后一个疑问，不太理解。
个人理解是，一个是自旋相反相容成键，一个是自旋相同排斥反键。

相同相位的波瓣相互叠加振幅增大，反之减小，在两个原子间波函数振幅增大则电子概率密度增大，在核的电势场里的势能下降，体系能量下降，就是成键轨道