A configuration interaction study of the ground and first excited <sup>1</sup>∑<sup>+</sup> states of the NaI molecule

Sakai, Yoshiko; Miyoshi, Eisaku; Anno, Tosinobu

doi:10.1139/v92-044

Cited by 21 publications

(30 citation statements)

References 27 publications

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“…The change in the sign of the adiabatic dipole moments at the crossing is due to change in the character of the ionic or covalent wave functions. The computed dipole moment at the experimental equilibrium distance of the NaI ground state is 9.44 Debye, in good agreement with the value of 9.41 Debye by Sakai et al 10 and the experimental value of 9.21 Debye by Hebert et al 24 The electronic Hamiltonian matrix relevant to the 0 ϩ adiabatic potential curves shown in Fig. 2 where the matrix elements a, b, and c are, respectively, the Fig.…”

Section: Potential Curvessupporting

confidence: 87%

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Spin–orbit effects in photodissociation of sodium iodide

Alekseyev

Liebermann

Buenker

et al. 2000

The Journal of Chemical Physics

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Articles you may be interested inQuartet states of the acetylene cation: Electronic structure calculations and spin-orbit coupling terms Extensive ab initio study of the valence and low-lying Rydberg states of BBr including spin-orbit coupling Photodissociation of alkyl and aryl iodides and effect of fluorination: Analysis of proposed mechanisms and vertical excitations by spin-orbit ab initio study Ab initio spin-orbit CI calculations of the potential curves and radiative lifetimes of low-lying states of lead monofluoride Ab initio configuration interaction calculations of the electronic binding energies, spin-orbit coupling matrix elements and transition dipole moments of NaI are presented. The results are used to construct adiabatic and diabatic representations of the 0 ϩ molecular states relevant to predissociation. The dynamics of photopredissociation is elucidated by multichannel time-dependent wave packet propagation in the diabatic representation. Specific features associated with the spatial and temporal evolution of the wave packet are ascribed to those observed in femtosecond pump-probe experiments. In particular, the rate of decay of the electronically excited NaI* complex is found to be in close agreement with time-resolved experimental studies. Partial photoabsorption cross sections for the production of iodine atoms in the ground ( 2 P 3/2 ) and excited ( 2 P 1/2 ) spin-orbit states are calculated and found to peak at excitation wavelengths of 322 and 263 nm, respectively, in accord with experimental data.

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Section: Potential Curvessupporting

confidence: 87%

“…The atomic basis set employed for Na has been taken from Ref. 10 and consists of (6s6p3d)/͓5s5p3d͔ Gaussian orbitals. The iodine atomic basis is an uncontracted set (6s7 p3d1 f ) and is described in more detail in our previous work.…”

Section: Ab Initio Calculationsmentioning

confidence: 99%

Spin–orbit effects in photodissociation of sodium iodide

Alekseyev

Liebermann

Buenker

et al. 2000

The Journal of Chemical Physics

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“…5,6,15 Overall, the NaI potentials are in reasonable agreement, not only with experiment but also with high-level ab initio calculations. 9,11 2. SolVation and Water Potentials.…”

Section: Computational Methodologymentioning

confidence: 99%

Nonadiabatic Trajectory Studies of NaI(H₂O)_n Photodissociation Dynamics

et al. 2006

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We have investigated the photodissociation dynamics of NaI(H(2)O)(n) [n = 1-4] clusters using the molecular dynamics with quantum transitions method and a quantum mechanics/molecular mechanics description of NaI(H(2)O)(n), which involves a semiempirical valence-bond approach to describe the NaI electronic structure and classical solvent-solvent and solute-solvent interaction potentials. Our simulation results show that the NaI(H(2)O)(n) excited-state population decay upon reaching the NaI curve-crossing region increases with cluster size due to the stabilization of the ionic branch of the NaI excited state by the surrounding water molecules, and the resulting increase in nonadiabatic transition probability. After reaching the curve-crossing region for the first time, however, the excited-state population decay resembles that of bare NaI because of rapid evaporation of 99% and 95% of the water molecules for NaI(H(2)O) and NaI(H(2)O)(n) [n = 2-4], respectively. This extensive evaporation is due to the reversed NaI polarity in the Franck-Condon region of the NaI first excited state, which causes strong repulsive NaI-H(2)O forces and induces rapid nonstatistical water evaporation, where product water molecules are formed more rotationally than translationally hot. A few water molecules (5% or less) remain transiently or permanently bound to NaI, forming long-lived clusters, when NaI remains predominantly ionic, i.e., remains in the excited state, after reaching the curve-crossing region. To connect simulation results with experiment, we have simulated femtosecond probe signals resulting from two-photon and one-photon excitation to the X and I NaI(+) probe states. In agreement with experimental findings, the probe signals resulting from the two-photon probe scheme, where excitation occurs from the covalent branch of the excited state, decay exponentially over the NaI first excited-state vibrational period, with very little evidence of long-time dynamics. The one-photon probe scheme (not used for experimental cluster studies) is shown to be less sensitive to solvation, in that excitation energies will remain similar over a range of cluster sizes, as the ionic branch of the excited state and the NaI(+) probe states are stabilized to the same extent by the presence of water molecules. The resulting probe signals are also more revealing of the NaI(H(2)O)(n) photodissociation dynamics than the two-photon probe signals, as they may allow monitoring of solvation effects on the NaI nonadiabatic dynamics and of successive evaporation of water molecules. Time-resolved photoelectron spectra provide limited additional information regarding the NaI(H(2)O)(n) photodissociation dynamics. A key consequence of the rapid water evaporation demonstrated here is that experimentally observed signals may arise from the photodissociation of much larger NaI(H(2)O)(n) parent clusters.

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“…4,6,8 Measurements of the adiabatic escape probability coupled with application of the Landau-Zener formalism for dynamical curve crossing lead to a value of V 12 (R x ) ) 415 cm -1 for the coupling matrix element between covalent and ionic Ω ) 0 + states, in close agreement with previous theoretical and experimental values. [13][14][15][16][17][18] Of relevance to the experiments described in the current work is a point raised previously by Rose et al concerning the appearance of the time-resolved fluorescence transient, 6 namely, that if absorption of the probe pulse by Ψ 2 (R;t) on the A 0 + potential takes place over a restricted range of coordinates centered about a particular R, then the second and subsequent real-time fluorescence peaks should comprise two closely separated maxima, corresponding to inward and outward bound propagation of the wave packet through the optically coupled region (OCR) defined by the probe pulse. 19,20 An attempt was made by Rose et al to observe such structure in the FTS transient by decreasing the pulse width of the probe laser; nevertheless, the anticipated splitting of the fluorescence peaks into a doublet line shape remained unobserved, though an increase in the width of the second peak relative to the first was noted.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond Real-Time Probing of Reactions. 18. Experimental and Theoretical Mapping of Trajectories and Potentials in the NaI Dissociation Reaction

et al. 1996

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We describe a method of tracking wave packet trajectories by probing both the temporal and spatial evolution of a coherent state prepared by a femtosecond laser pulse in real time. Application to the NaI dissociation reaction illustrates this technique, in which the direction of wave packet propagation within the quasi-bound A 0 + potential is observed and correlated to the physical processes of extension and contraction of the Na-I bond. From the combination of spatial and temporal information observed from experiments, self-consistent potential energy functions for the A 0 + state and the higher-lying state accessed by the probe laser pulse are constructed. The dynamics and the validity of the potentials so derived are tested via semiclassical and quantum-dynamical simulations of the wave packet motion, and comparisons with potentials obtained from other methods are drawn.

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A configuration interaction study of the ground and first excited ¹∑⁺ states of the NaI molecule

Cited by 21 publications

References 27 publications

Spin–orbit effects in photodissociation of sodium iodide

Spin–orbit effects in photodissociation of sodium iodide

Nonadiabatic Trajectory Studies of NaI(H₂O)_n Photodissociation Dynamics

Femtosecond Real-Time Probing of Reactions. 18. Experimental and Theoretical Mapping of Trajectories and Potentials in the NaI Dissociation Reaction

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A configuration interaction study of the ground and first excited 1∑+ states of the NaI molecule

Cited by 21 publications

References 27 publications

Spin–orbit effects in photodissociation of sodium iodide

Spin–orbit effects in photodissociation of sodium iodide

Nonadiabatic Trajectory Studies of NaI(H2O)n Photodissociation Dynamics

Femtosecond Real-Time Probing of Reactions. 18. Experimental and Theoretical Mapping of Trajectories and Potentials in the NaI Dissociation Reaction

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A configuration interaction study of the ground and first excited ¹∑⁺ states of the NaI molecule

Nonadiabatic Trajectory Studies of NaI(H₂O)_n Photodissociation Dynamics