钾7S态与基态铷原子的碰撞能量转移

Collisional Energy Transfer of the K(7S) State by Ground State Rb Atoms

在Ｋ－Ｒｂ混合蒸气中，使用Ｋ光谱灯和染料激光器，将Ｋ原子二步激发到７Ｓ态，用荧光法测量了过程Ｋ（７Ｓ）＋Ｒｂ（ＳＳ）→Ｋ（４Ｓ）＋Ｒｂ７２ＤＪ的碰撞转移截面。Ｒｂ７２ＤＪ对Ｋ７Ｓ的荧光比中含有Ｒｂ７２Ｄ能级混合的影响，第二个实验可以消除这个影响，利用Ｒｂ光谱灯和染料激光器产生Ｒｂ７２Ｄ３／２态，探测Ｒｂ７２Ｄ５／２对Ｒｂ７２Ｄ３／２的荧光比。在Ｔ＝４２５Ｋ时，得到Ｋ７Ｓ→Ｒｂ７２ＤＪ激发转移截面（１０－１４ｃｍ２单位）分别为２．０８±０．７７（＝３／２）和２．８６±１．０６（Ｊ＝５／２）。

Two-photon stepwise excitation of potassium atoms in the ground state using apotassium lamp and a CW dye laser populated the K7S state in the K-Rb vapor mixtures.The cross sections for the collisional process K(7S)+Rb(SS) →K(4S)+Rb(7DJ) havebeen measured by observation of the resulting fluorescence. The ratio of Rb 7D to K7S fluorescence contained a contribution from mixing in the 7D levels. The contributioncould effectively be subtracted out using a second experiment in which a rubidium lampand a CW dye laser were used to pump the 7 2D3/2 state, and the ratio of 7D5/2 to 7D3/2fluorescence was monitored. The cross sections (in 10-14 cm2) for K(7S) → Rb(7DJ)excitation transfer for J being 3/2, 5/2 at the temperature of 425 K were 2.08±0.77 and2.86±1 .06, respectively.