Abstract
Multireference configuration interaction calculations have been carried out for low-lying electronic states of AsH_{3}. Bending potentials for the nine lowest states of AsH_{3} are obtained in C _{3v } symmetry for As–H distances fixed at the ground state equilibrium value of 2.850 a _{0}, as well as for the minimum energy path constrained to R _{1} = R _{2} = R _{3}. The calculated equilibrium geometry and bond energy for the ground state agree very well with the previous experimental and theoretical data. It is shown that the lowest excited singlet state belongs to the ^{1} A _{1} symmetry (in C _{3v }), in contradiction to the previous calculations. This state is characterized by a planar equilibrium geometry. Asymmetric stretch potential energy surface (PES) cuts along the H_{2}As–H recoil coordinate (at R _{1} = R _{2} = 2.850 a _{0}, θ = 123.9° and 90°) for numerous excited states and two-dimensional PESs for the and states up to the dissociation limits are obtained for the first time. The transition moments are calculated as well and used together with the PES data for the analysis of possible photodecay channels of arsine in its first absorption band.
The authors are very grateful for useful discussions with Professor C. Wittig and Dr. W. P. Schroeder. We would also like to express our gratitude to the Forschungsgemeinschaft (DFG) for its financial support in the frame of Project BU 450/21-2.
I. INTRODUCTION
II. COMPUTATIONAL METHOD
III. RESULTS AND DISCUSSION
A. Bending potential energy curves
B. PESs along the H_{2}As–H recoil coordinate
C. Transition moments
IV. CONCLUSION
Key Topics
- Ground states
- 19.0
- Dissociation
- 18.0
- Excitation energies
- 13.0
- Dissociation energies
- 11.0
- Rydberg states
- 11.0
Figures
Bending PESs for the low-lying states of AsH_{3} computed at R = 2.850 a _{0} = without including SO coupling. The A _{1} states are shown in black, the E states in red, the singlet states with solid lines and closed circles, the triplet states with dashed lines and open circles. The vertical dashed line indicates the equilibrium angle (θ = 123.9°) for the ground state.
Bending PESs for the low-lying states of AsH_{3} computed at R = 2.850 a _{0} = without including SO coupling. The A _{1} states are shown in black, the E states in red, the singlet states with solid lines and closed circles, the triplet states with dashed lines and open circles. The vertical dashed line indicates the equilibrium angle (θ = 123.9°) for the ground state.
Minimal-energy-path PESs for the low-lying states of AsH_{3} computed in C _{3v } symmetry (R _{1} = R _{2} = R _{3}) without including SO coupling. Notation is the same as in Fig. 1.
Minimal-energy-path PESs for the low-lying states of AsH_{3} computed in C _{3v } symmetry (R _{1} = R _{2} = R _{3}) without including SO coupling. Notation is the same as in Fig. 1.
PES along the H_{2}As–H recoil coordinate for the low-lying states of AsH_{3} computed without including SO coupling for R _{1} = R _{2} = 2.850 a _{0} and θ = 123.9°. The ^{1} A ^{′} states are shown in black, ^{1} A ^{″} in red, ^{3} A ^{′} in blue, ^{3} A ^{″} in green.
PES along the H_{2}As–H recoil coordinate for the low-lying states of AsH_{3} computed without including SO coupling for R _{1} = R _{2} = 2.850 a _{0} and θ = 123.9°. The ^{1} A ^{′} states are shown in black, ^{1} A ^{″} in red, ^{3} A ^{′} in blue, ^{3} A ^{″} in green.
PES along the H_{2}As–H recoil coordinate for the low-lying states of AsH_{3} computed without including SO coupling for R _{1} = R _{2} = 2.850 a _{0} and θ = 90° (planar geometry). The ^{1} A ^{′} states are shown in black, ^{1} A ^{″} in red, ^{3} A ^{′} in blue, ^{3} A ^{″} in green.
PES along the H_{2}As–H recoil coordinate for the low-lying states of AsH_{3} computed without including SO coupling for R _{1} = R _{2} = 2.850 a _{0} and θ = 90° (planar geometry). The ^{1} A ^{′} states are shown in black, ^{1} A ^{″} in red, ^{3} A ^{′} in blue, ^{3} A ^{″} in green.
Calculated 2D PESs for the and states of AsH_{3} as functions of one As–H distance and the θ angle. The other two As–H distances are fixed at the ground state equilibrium value of 2.850 a _{0}.
Calculated 2D PESs for the and states of AsH_{3} as functions of one As–H distance and the θ angle. The other two As–H distances are fixed at the ground state equilibrium value of 2.850 a _{0}.
Calculated transition moments (red) and (blue) obtained as functions of the θ angle in the C _{3v } group for R _{1} = R _{2} = R _{3} = 2.850 a _{0} (see text).
Calculated transition moments (red) and (blue) obtained as functions of the θ angle in the C _{3v } group for R _{1} = R _{2} = R _{3} = 2.850 a _{0} (see text).
Calculated transition moments for Cartesian components of the and transitions obtained as functions of the H_{2}As–H recoil coordinate for R _{1} = R _{2} = 2.850 a _{0} and θ = 123.9°.
Calculated transition moments for Cartesian components of the and transitions obtained as functions of the H_{2}As–H recoil coordinate for R _{1} = R _{2} = 2.850 a _{0} and θ = 123.9°.
Tables
Equilibrium H–X–H angles α and bending angles θ, and inversion barriers E _{ inv } for the and states of the XH_{3} molecules. θ = 90° corresponds to planar geometry.
Equilibrium H–X–H angles α and bending angles θ, and inversion barriers E _{ inv } for the and states of the XH_{3} molecules. θ = 90° corresponds to planar geometry.
Technical details of the MRD–CI calculations of AsH_{3} in C _{ s } symmetry at T = 0.1 μE _{ h }. N _{ ref } and N _{ root } refer to the number of reference configurations and roots treated, respectively. SAFTOT designates the total number of generated spin-adapted functions (SAF), and SAFSEL the number of selected SAFs at R _{ e } = 2.850 a _{0} and θ_{ e } = 123.9°.
Technical details of the MRD–CI calculations of AsH_{3} in C _{ s } symmetry at T = 0.1 μE _{ h }. N _{ ref } and N _{ root } refer to the number of reference configurations and roots treated, respectively. SAFTOT designates the total number of generated spin-adapted functions (SAF), and SAFSEL the number of selected SAFs at R _{ e } = 2.850 a _{0} and θ_{ e } = 123.9°.
MRD–CI geometries, vertical excitation energies E _{ vert } and energies E for selected features in the bending potentials of AsH_{3}. Notation min and max used in the third column corresponds to the global and local extrema in the Λ − S bending PESs.
MRD–CI geometries, vertical excitation energies E _{ vert } and energies E for selected features in the bending potentials of AsH_{3}. Notation min and max used in the third column corresponds to the global and local extrema in the Λ − S bending PESs.
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