Two-photon dissociation of nitric oxide

利用脉冲激光技术研究了NO和N2 O的双光子解离过程，在235 ~ 240 nm波长范围内，N2 O被双光子解离。N（^2D）、N（^2P）和NO（v=1）可以通过共振增强多光子电离技术结合飞行时间质谱技术检测到。同时还进行了N（^2D）和N（^2P）的多普勒轮廓测量。从多普勒轮廓的宽度，它是可能的，以确定这些物种在实验室框架中的最大速度。与光解离过程的速率比较表明，这些物种是在N_2O的双光子解离过程中形成的，三光子超激发态对这些物种的解离可以忽略.测量了N（^2D）、N（^2P）和NO（v=1）以及母体N_2O^+离子的产额与激发激光波数的函数关系。可以观察到3 psigma ^1 II-X ^1 SIGMA ^+跃迁的振动结构。发现激发到2^1_（SIGMA^+）态比激发到其他振动能级如1^1_和2^1_（DELTA）态更能促进解离成中性粒子。这表明预离解是通过C_S对称性中的离解A '态进行的。在275 nm附近的NO双光子解离中，可以检测到N（^2D）和O（^3P）的产物。N（^4S）在我们所尝试的范围内是无法检测到的。比较了N（^2D）和O（^3P）的作用光谱。这表明N（^2D）和O（^3P）的产生是主要的出口通道。

Two-photon dissociation processes of nitric oxide and nitrous oxide were studied by using pulsed laser techniques.N_2O was two-photon photolyzed between 235 and 240 nm under beam conditions. N (^2D), N (^2P), and NO (v=1) could be detected as products by a resonance-enhanced multiphoton ionization technique combined with a time-of-flight mass'spectrometric technique. The Doppler profile measurements of N (^2D) and N (^2P) were also carried out. From the widths of the Doppler profiles, it is possible to determined the maximum velocities of these species in the laboratory frame. Comparison of these velocities with those expected from the exothermicities of the photodissociation processes showed that these species are formed in the two-photon dissociation of N_2O.Dissociation of the three-photon super excited states to these species can be ignored. The yields of N (^2D), N (^2P), and NO (v=1) as well as that of parent N_2O^+ ions were measured as a function of the wavenumber of the excitation laser. Vibrational structures attributable to 3psigma ^1II-X^1SIGMA^+ transition could be observed. Excitation to the 2^1_ (SIGMA^+) state was found to promote the dissociation to neutral species compared to the excitation to other vibrational levels such as the 1^1_ and 2^1_ (DELTA) states. This suggests that the predissociation proceeds via a dissociative A'state in the C_S symmetry. One of the strongest candidates is the 5^1A'state.In the two-photon dissociation of NO around 275 nm, N (^2D) as well as O (^3P) could be detected as products. N (^4S) could not be detected as far as we tried. The action spectra of N (^2D) and O (^3P) were compared. They were similar suggesting that the production of N (^2D) and O (^3P) should be the main exit channe.