Na_2(~3Λ_u)高位态的预解离和碰撞转移  

Predissociation and Collisional Transfer of the High-Lying State of the Na_2(~3∧_u)

作　　者：王雪燕[1] 周冬冬[1] 王大贵[1] 穆尼赛[1] 戴康[1] 沈异凡[1] 

机构地区：[1]新疆大学物理科学与技术学院,新疆乌鲁木齐830046

出　　处：《中国激光》2010年第4期996-999,共4页Chinese Journal of Lasers

基　　金：国家自然科学基金(10664003)资助课题

摘　　要：利用光学-光学双共振光谱技术,测量了Na_2(~3Λ_u)态的预解离率以及与Na基态原子的碰撞转移率。样品池温度控制在553～703 K之间,用532 nm连续激光激发Na_2(1~3∑_u^+)至Na_2(1~3∑_g^+)态,调频脉冲激光器将1~3∑_g^+激发至~3Λ_u高位态。在不同的Na密度下记录~3Λ_u→1~3Σ_g^+跃迁的时间分辨光强,得到~3Λ_u的有效寿命。由Stern-Volmer方程得到~3Λ_u态的辐射率与预解离率之和为(4.8±1.2)×10~7s^(-1),而总的碰撞去布居截面为(2.7±0.5)×10^(-14)cm^2。测量Na_2分子的~3Λ_u→1~3Σ_g^+以及Na原子的5S→3P,3D→3P辐射跃迁的时间积分光强。由光强比得到Na_2(~3Λ_u)向Na(3D)的预解离率为(8.0±2.4)×10~6s^(-1),Na_2(~3Λ_u)→Na(5S,3D)的碰撞转移截面分别为σ_(5S)=(6.2±1.9)×10^(-15)cm^2,σ_(3D)=(1.1±0.3)×10^(-15) cm^2。The 3Λu state of Na2 is excited by using optical-optical double resonance spectroscopy.The predissociative rates and collisional transfer rates of 3Λu state are experimentally measured.The cell temperature varies between 553 K and 703 K.A continuous-wave（CW） all-solid-state green laser（532 nm） is used to pump Na2 from ground state 1 3Σu＋ to the 1 3Σg＋.Then an optical parameter oscillator（OPO） laser is used to excite high-lying 3Λu state.From time-resolved fluorescence for the 3Λu→1 3Σg＋ transition at different Na densities,the effective lifetimes of the Na2（3Λu） state are yielded.Based on the Stern-Volmer equation,the sum of the radiative and predissociative rates is obtained with（4.8±1.2）×107 s（-1）,and the total cross section for deactivation of the Na2（3Λu） by means of collisions with Na is（2.7±0.5）×10（-14） cm2.With different Na densities,the time-integrated intensities of 3Λu→1 3Σg＋,5S→3P and 3D→3P radiative transition are measured.The intensity ratios versus the Na densities can be fitted by the straight lines.From the slopes and the intercepts,we obtain predissociative rate of（8.0±2.4）×106 s（-1） from Na2（3Λu） to Na（3D）,and the cross sections of（6.2±1.9）×10（-15） cm2 and（1.1±0.3）×10（-15） cm2 for collisional energy transfer from Na2（3Λu） to Na（5S） and from Na2（3Λu） to Na（3D）,respectively.

关 键 词：光谱学 碰撞转移 预解离 时间分辨荧光 时间积分光强 Na2分子 

分 类 号：O562.5[理学—原子与分子物理] O657.38[理学—物理]