The spontaneous emission phenomenon of an excited atom is one of basic processes in quantum optics.

激发态原子的自发辐射现象是量子光学领域是最基本的过程之一。

youdao

Both interactions of a two-level atom with a vacuum field and a excited atom with a coherent field, as examples, are discussed in detail.

作为例子，详细讨论了二能级原子与真空场的相互作用以及处于激发态的原子与相干场的相互作用。

youdao

When they breakthrough, they collide with atoms and molecules, which take some of the energy and store it, creating what's known as an excited atom.

冲破大气层过程中，这些高能粒子与高层大气的原子或分子碰撞，促使这些原子或分子吸收一部分的能量并将其储存，产生一种所谓的激发态原子。

youdao

So if we're talking about the fourth excited state, and we talk instead about principle quantum numbers, what principle quantum number corresponds to the fourth excited state of a hydrogen atom.

如果我们说的是,第四激发态，我们用,主量子数来描述，哪个主量子数对应了,氢原子的第四激发态？

麻省理工公开课 - 化学原理课程节选

So, what we know is happening is that were having transitions from some excited states to a more relaxed lower, more stable state in the hydrogen atom.

我们知道，这里所发生的是,氢原子从激发态到更低更稳定的态的跃迁，而我们用眼睛可以探测到的。

麻省理工公开课 - 化学原理课程节选

So another way to say that is, in a sense, if we're thinking about the excited state of a hydrogen atom, the first excited state, or the n equals 2 state, what we're saying is that it's actually bigger than the ground state, or the 1 s state of a hydrogen atom.

换句话说，如果我们激发一个氢原子，第一激发态或者说ｎ等于２的态，我们说它比氢原子基态,或者说１ｓ态要大。

麻省理工公开课 - 化学原理课程节选

Once that is done, another laser pulse will jostle the virus from its ground state into an excited state, just as a single atom is excited by moving one of its electrons from a lower to a higher orbital.

ECONOMIST: An old thought experiment may soon be realised