Hans Veenhuizen

The HeI excited electron spectrum of phosphine : AN EXPERIMENTAL AND THEORETICAL-STUDY

The HeI excited electron spectrum of phosphine (PH3) has been recorded with high resolution. The 2 A 1 band reveals an extensive vibrational progression in the v 2 bending mode with irregular structure at the low binding energy side due to hindered inversion. The existence of a barrier in the PH3 + 2 A 1 ionic state has been confirmed by vibrational energy level and Franck-Condon factor calculations based on CASSCF calculations of the total energy. The equilibrium angle between a P-H bond and the plane of the three hydrogen atoms in this ionic state was determined to be 15·5° and the barrier against inversion to be 160 meV. The adiabatic electron binding energy of this transition ([Xtilde] 2 A 1 ←X 1 A 1) was found to be 9·868±0·005 eV.

High-resolution UV photoelectron spectrum of CO2

Abstract The highly-resolved HeI photoelectron spectrum of CO 2 is presented and its vibrational structure studied in detail. In the X 2 Π g ionic state the v 3 antisymmetric mode is found to be excited in double quanta ( v 1- v 2- v 3 = 0. 0. 2) with energy hv 3 = 181 meV. In the C 2 Σ g + state a single quantum of the same mode is found to be excited ( hv 3 = 189 meV) in combination with a v 1 excitation. Vibronic interaction with vibrational levels in the B 2 Σ u + state of the ion is suggested to promote this (1, 0, 1) excitation. It is established that inelastic scattering processes contribute to the vibrational structure in the C 2 Σ g + band. The spin-orbit splitting in the X 2 Π g is determined to be 19±1 meV and 10±2 eV in the Ā 2 Π u state. Vibronic structure is resolved in the X 2 Π g band where the Renner-Teller coupling constant is determined to be ϵ = 0.21±0.02 and the vibrational energy of the v 2 mode as 60±7 meV. In the Ā 2 Π u state the v 2 energy is found to be hv 2 = 60 meV from the observed hot-band structure.

A theoretical investigation of the U.V. excited 1 A 1→2 A 1 photoelectron spectra of NH3 and ND3

The vibronic spectra of the 1 A 1→2 A 1 U.V. photoelectron transitions in NH3 and ND3 are analysed theoretically. Optimum geometry and potential curves are obtained by means of ab initio configuration interaction calculations. A one-dimensional approach, using the decoupled planar upper state symmetry coordinates and a Manning type function for the double-minimum potentials, is found to account for frequency shifts, anharmonicity and isotope shifts in the 3a 1 electron ionization. The intensities of the photoelectron spectrum are redetermined through integration of the experimental vibronic bands and are furthermore computed within the Franck-Condon approximation. From calculations of hot band progressions the first adiabatic ionization potentials of NH3 and ND3 could be set to 10·073 and 10·12 eV, respectively.

A study of the vibronic structure in the HeI excited photoelectron spectrum of CO2 involving the X 2Πg and A 2Πu ionic states

A study of the vibronic structure in the HeI excited photoelectron spectrum of CO2 involving the X 2Pig and A 2Piu ionic states

Vibrational structure in the valence electron spectra of pyridine and pyridine-d5

Abstract The He(I) electron spectra of pyridine and pyridine- d 5 have been recorded. Distinct vibrational progressions are observed in the first and fourth electronic bands and a vibrational analysis is made. The isotopic effect on the vibrational energies is found to be helpful in the assignment of the vibrational peaks. By consideration of highly resolved spectra the vibrational interpretation of certain bands in the photoelectron spectra of pyridine and pyridine- d 5 has been accomplished. The spectra of the two species display differences due to isotope exchange but are nevertheless similar in structure. This is of great help in the vibrational assignment.

Inelastic scattering and satellite fine structure in the high-resolution uv photoelectron spectrum of CS2

Abstract The outer valence region in CS 2 has been studied by high-resolution UV photpelectron Spectroscopy. The spectra reveal detailed vibrational structure in the X

High resolution angle-resolved photoelectron spectrum of CO2, excited with polarized resonance radiation

2 Π g , A

Bowen excitation of NIII lines in symbiotic stars

2 Π u , B

Modeling of C IV pumped fluorescence of Fe II in symbiotic stars

2 Σ + u and C

Angular distribution of photoelectrons from p levels in Ar, Kr and Xe close to threshold

2 Σ + g bands. Some of the fine-structure peaks in the X , B