Vall-Llosera G, Melero García E, Kivimäki A, Rachlew E, Coreno M, de Simone M, Richter R, Prince K C
Royal Institute of Technology, Department of Physics, AlbaNova University Center, 10691 Stockholm, Sweden.
Phys Chem Chem Phys. 2007 Jan 21;9(3):389-95. doi: 10.1039/b610199b. Epub 2006 Nov 24.
Visible-UV fluorescence emission of gas-phase hydrogen sulfide, H(2)S, has been studied at the S 2p edge with synchrotron radiation excitation. Dispersed fluorescence measurements in the wavelength range 300-900 nm were taken at several photon energies corresponding to the excitations of the S 2p electrons to the unoccupied molecular and Rydberg orbitals. The spectra reveal fluorescence from the H, S, S(+), HS and HS(+) photo-fragments. H is found to be the strongest emitter at Rydberg excitations, while the emission from S(+) is dominant at the molecular resonances and above the S 2p ionization thresholds. The intensities of hydrogen Lyman-alpha (122 nm), Balmer-alpha (656 nm), Balmer-beta (486 nm) transitions as well as the visible-UV total fluorescence yield (300-900 nm) and the total ion yield were measured by scanning the photon energy in small steps across the S 2p edge. The different Balmer lines show some sensitivity to the specific core excitations, which is, however, not so strong as that recently observed in the water molecule [E. Melero García, A. Kivimäki, L. G. M. Pettersson, J. Alvarez Ruiz, M. Coreno, M. de Simone, R. Richter and K. C. Prince, Phys. Rev. Lett., 2006, 96, 063003].
利用同步辐射激发，在S 2p边对气相硫化氢（H₂S）的可见-紫外荧光发射进行了研究。在对应于S 2p电子激发到未占据分子轨道和里德堡轨道的几个光子能量下，进行了300 - 900 nm波长范围内的色散荧光测量。光谱显示了来自H、S、S⁺、HS和HS⁺光碎片的荧光。发现H在里德堡激发时是最强的发射体，而S⁺的发射在分子共振处以及高于S 2p电离阈值时占主导。通过在S 2p边以小步长扫描光子能量，测量了氢莱曼α（122 nm）、巴尔末α（656 nm）、巴尔末β（486 nm）跃迁的强度以及可见-紫外总荧光产率（300 - 900 nm）和总离子产率。不同的巴尔末线对特定的芯激发表现出一定的敏感性，然而，这种敏感性不如最近在水分子中观察到的那么强[E. 梅勒罗·加西亚、A. 基维马基、L. G. M. 彼得松、J. 阿尔瓦雷斯·鲁伊斯、M. 科雷诺、M. 德西蒙、R. 里希特和K. C. 普林斯，《物理评论快报》，2006年，96，063003]。
