利用光学-光学双共振研究谱线的碰撞增宽

利用光学-光学双共振光谱技术研究了NaK分子21Σ＋→６1Σ＋跃迁线的碰撞增宽。一台单模半导体激光器实现11Σ＋(v″，J″)→21Σ＋(v′，J′)的跃迁，另一单模半导体激光器激发21Σ＋(v′，J′)能级到６1Σ＋的振转能级，二激光束反向平行通过样品池。谱线总线宽与K原子密度成线性关系，由其斜率得到增宽速率系数k_br＝(1.4±0.7)×10-8 cm3·s-1。同时研究了21Σ＋(v＝8，J＝12)→21Σ＋(v＝8，J＝13，14)转动能级间的碰撞激发转移，测量谱线的相对强度，由速率方程得到碰撞转移速率分别为6.1×106和5.2×106 s-1。

Study of Collisional Broadening of Spectral Line by Optical-Optical Double Resonance

The collisional broadening of the 2(1)sigma+ --> 6(1)sigma+ line of NaK molecule was studied using the optical-optical double resonance technique. A single-mode diode laser was set to a particular 1(1)sigma+ (v", J") --> 2(1)sigma+ (v',J') transition. Another single-mode diode laser was then used to excite the molecule from 2(1)sigma+ (v', J') level to the rovibrational level of 6(1)sigma+. The two laser beams counterpropagated through the cell. The broadening rate coefficient was determined from the slope of the total linewidth versus potassium density curve. The rate coefficient, k(br) = (1.4+/-0.7) x 10(-8) cm3 x s(-1), was obtained. The collisional excitation transfer between rotational levels of the 2(1)sigma+ state i. e., 2(1)sigma+ (v = 8, J = 12) --> 2(1)sigma+ (v = 8, J = 13, 14)] was also investigated. The rates can be determined from the relative intensities of the main peak and satellite lines, combined with a rate equation model. The rates are 6.1 x 10(6) and 5.2 x 10(6) s(-1) respectively.