Infrared multiphoton excitation of polyatomic molecules

Results of investigations of the process of multiphoton excitation of polyatomic molecules by CO₂-laser radiation are presented. The mechanism of formation of the profiles of IR absorption bands of polyatomic molecules is discussed. New experimental methods of investigation of relaxation processes at high levels of vibrational excitation of molecules in the ground and triplet states are considered. For vapors of polyatomic molecules and their mixtures with foreign gases, the quantitative characteristics of the collisional exchange and the vibrational-energy transfer as well as the rates of intercombinational conversion ⇛ and triplet-triplet transfer are presented and their dependences on the vibrational-excitation level are discussed. Institute of Molecular and Atomic Physics of the National Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 5, pp. 675–693, September–October, 1998.     

Molecular ion yield enhancement induced by gold deposition in static secondary ion mass spectrometry

Static ToF-SIMS was used to evaluate the effect of gold condensation as a sample treatment prior to analysis. The experiments were carried out with a model molecular layer (Triacontane M = 422.4 Da), upon atomic (In⁺) and polyatomic (Bi₃⁺) projectile bombardment. The results indicate that the effect of molecular ion yield improvement using gold metallization exists only under atomic projectile impact. While the quasi-molecular ion (M+Au)⁺ signal can become two orders of magnitude larger than that of the deprotonated molecular ion from the pristine sample under In⁺ bombardment, it barely reaches the initial intensity of (M−H)⁺ when Bi₃⁺ projectiles are used. The differences observed for mono- and polyatomic primary ion bombardment might be explained by differences in near-surface energy deposition, which influences the sputtering and ionization processes.     

动态反应池-电感耦合等离子体质谱法测定土壤中重金属元素

用微波消解/动态反应池-电感耦合等离子体质谱法测定土壤中的重金属。研究了微波消解以及影响测定的因素(多原子离子干扰及盐度等),研究表明:引入动态反应气NH3可有效消除多原子离子干扰;盐度小于2.0 g/L测定结果比较可靠。方法检出限为0.008~0.32μg/L,回收率为92%~109%。已应用于土壤样品的测定。     

球形弹对金属靶板侵彻问题的数值模拟

基于球形空穴膨胀模型(SCE),采用ABAQUS有限元商业软件并结合自主开发的ABAQUS用户子程序对球形弹侵彻金属靶进行了有限元3D数值模拟。根据空穴膨胀理论,靶体对侵彻弹体的影响可以用一个作用在弹体表面的力函数代替,这样在进行数值模拟时就无需划分靶体网格,也避免了复杂的接触问题,从而使模拟大大简化。模拟过程中考虑到弹体的可变形性和入射时的微小偏航角,并且考虑了弹体在运动过程中和靶体的接触分离效应。模拟结果与文献中的实验结果进行了比较,模拟结果与实验结果吻合得很好。