TY - JOUR
T1 - Superexcitation and subsequent decay of triatomic molecules studied by two-dimensional photoelectron spectroscopy
AU - Mitsuke, Koichiro
AU - Hattori, Hideo
AU - Hikosaka, Yasumasa
N1 - Funding Information:
Our thanks are due to the members of the UVSOR for their valuable help during the course of the experiments. This work has been supported financially in part by national funds appropriated for special research projects of the Institute for Molecular Science, by a Grant-in-Aid for Scientific Research (Grant No. 10640504) from the Ministry of Education, Science, Sports, and Culture, Japan, and by a grant for scientific research from Matsuo Foundation.
PY - 2000/11
Y1 - 2000/11
N2 - Photoionization and photodissociation processes of SO2 and CS2 in vacuum UV are studied by using two-dimensional photoelectron spectroscopy with a monochromatized synchrotron radiation source. The principal focus is on the mechanisms of autoionization and neutral dissociation of superexcited states. Photoelectron spectra of SO2 exhibit characteristic peaks at the electron kinetic energy below 1.8 eV which are assigned as resulting from autoionizing transitions of excited atomic sulfur, S*, into the ground S+(4S°) state. These S* atoms are in the singlet Rydberg states converging to S+(2D°). The precursor molecular states, SO*2, are considered to be multiple-electron excited Rydberg states lying at the photon energy above approximately 22 eV. The onset of the photoelectron yield due to the atomic autoionization accords with that expected from the thermochemical threshold for the formation of S* through three-body dissociation SO*2→S*+O+O. The two-dimensional photoelectron spectrum of CS2 provides tangible evidence for the formation of a dipole-forbidden Rydberg state (6σg)-1(3dσg)11Σg+ at the photon energy of 14.88 eV which autoionizes into the v3 = 1 vibrational state of the antisymmetric stretch v3 mode of CS2+ (X2Πg,Ω, Ω = 1/2 and 3/2). This Rydberg state is expected to borrow substantial oscillator strength from the (6σg)-1(5pσu)11Σu+ state through vibronic coupling involving the v3 vibration.
AB - Photoionization and photodissociation processes of SO2 and CS2 in vacuum UV are studied by using two-dimensional photoelectron spectroscopy with a monochromatized synchrotron radiation source. The principal focus is on the mechanisms of autoionization and neutral dissociation of superexcited states. Photoelectron spectra of SO2 exhibit characteristic peaks at the electron kinetic energy below 1.8 eV which are assigned as resulting from autoionizing transitions of excited atomic sulfur, S*, into the ground S+(4S°) state. These S* atoms are in the singlet Rydberg states converging to S+(2D°). The precursor molecular states, SO*2, are considered to be multiple-electron excited Rydberg states lying at the photon energy above approximately 22 eV. The onset of the photoelectron yield due to the atomic autoionization accords with that expected from the thermochemical threshold for the formation of S* through three-body dissociation SO*2→S*+O+O. The two-dimensional photoelectron spectrum of CS2 provides tangible evidence for the formation of a dipole-forbidden Rydberg state (6σg)-1(3dσg)11Σg+ at the photon energy of 14.88 eV which autoionizes into the v3 = 1 vibrational state of the antisymmetric stretch v3 mode of CS2+ (X2Πg,Ω, Ω = 1/2 and 3/2). This Rydberg state is expected to borrow substantial oscillator strength from the (6σg)-1(5pσu)11Σu+ state through vibronic coupling involving the v3 vibration.
UR - http://www.scopus.com/inward/record.url?scp=0034323757&partnerID=8YFLogxK
U2 - 10.1016/S0368-2048(00)00208-5
DO - 10.1016/S0368-2048(00)00208-5
M3 - 学術論文
AN - SCOPUS:0034323757
SN - 0368-2048
VL - 112
SP - 137
EP - 150
JO - Journal of Electron Spectroscopy and Related Phenomena
JF - Journal of Electron Spectroscopy and Related Phenomena
IS - 1-3
ER -