NO分子A^2Σ←X^2Π跃迁的激光双光子荧光激发谱

Laser Fluorescence Excited Spectrum of NO via A^2Σ←X^2Π Transition

以Nd :YAG脉冲激光器泵浦的光学参量发生器 放大器 (OPG OPA)作激发光源 ,获得了 4 2 0～ 4 72nm波长范围内NO分子的双光子激光荧光激发谱 ,并利用此技术对NO分子的能级结构进行了实验研究 ,将所得谱线峰归属为NO(A2 Σ←X2 Π)的跃迁 ,荧光强度随激光强度的二次方变化关系表明此过程是一双光子激发过程。利用实验所得峰值波长计算了NO(A2 Σ)态的基振动频率ωe 和平衡位置的力常数k。通过对NO分子A2 Σ→X2 Π跃迁的荧光时间分辨光谱进行实验研究 ,得到 2 6 6Pa气压下A2 Σ(v′ =0 )态的能级寿命τ=5 3 76ns。测量荧光寿命随气压的变化 ,利用曲线拟合得到NOA2 Σ(v′=0 ,1)

Two-photon fluorescence excited spectrum of NO induced by Nd:YAG laser pumped optical parameter generator/amplifier as excitation source was obtained in the range of 420 472 nm. With this technique, the structure of the energy levels of NO molecule in A 2Σ electronic state was investigated. The peaks of the spectrum were attributed to A 2Σ(v′=0,1)←X 2Π(v″=0) transition. The near square dependence of fluorescence signal on the laser intensity indicates a two photon process. The ground vibrational state oscillation frequency and the force constant of A 2Σ state were calculated. The fluorescence lifetime of A 2Σ(v′=0) state under the pressure of 266 Pa was also obtained by measuring fluorescence decay curve of A 2Σ(v′=0) states. It is about 53 76 ns. Fitting the curve of the fluorescence radiant lifetime versus pressure, the spontaneous radiant lifetimes and the rate coefficient of nonradiative transition relaxation of A 2Σ(v′=0,1) states were deduced.