Electronic state, excited, numerical model

In Reference [35], numerical examples of perturbative Sq - S2 excitation and the S2 IC dynamics for the / -carotene are discussed, too. The absence of reliable potential surfaces for this system motivated the use of a minimal two-dimensional model [66], which utilizes a Morse potential in each dimension. All three electronic surfaces Sq, and S2 involved in this example assume the same 2D potential form however, these potentials are shifted to each other. More importantly, in Ref. [35], each potential has 396 bound states in each electronic state within this model, while additionally the S2 and electronic states are coupled by linear coupling. Thus, the Q-space and P-space, as introduced in the context of the QP-algorithm in Section 1.3.1, consist of the S2 and 5 bound states, respectively. 

Emphasis is given in this note to the development of a model, which, with a modest numerical effort, can be used to incorporate the influence of an excited electronic state on the nuclear motion in the lowest electronic state. Such attempts have recently been undertaken by Shin and Lightl and followed up by Qi and Bowman. The rate of reactions, which are perceived to be well described by a ground state energy hypersurface, may be influenced to a considerable extent by excited electronic states. The simple model proposed in this note accommodates the interaction with one excited state and can be readily extended to several. Calculations are carried out and illustrate the effect of an excited state for varying degree of coupling. 

Numerical examples are shown in Figs. 7-9. The model system used is a 2D model of H2O in a continuous wave (CW) laser field of wavelength 515nm and intensity lO W/cm. The ground electronic state X and the first excited state A are considered. The bending and rotational motions are neglected for... 

In recent years numerous experiments have been reported on the fluorescence and energy transfer processes of electronically excited atoms. However, for flame studies the rates of many possible collision processes are not well known, and so the fate of these excited atoms is unclear. An interesting example concerns the ionization of alkali metals in flames. When the measured ionization rates are interpreted using simple kinetic theory, the derived ionization cross sections are orders of magnitude larger than gas kinetic (1,2,3). More detailed analyses (4,5) have yielded much lower ionization cross sections by invoking participation of highly excited electronic states. Evaluation of these models has been hampered by the lack of data on the ionization rate as a function of initial state for the alkali metals. 

The remainder of this paper is organized as follows In Sect. 5.2, we present the basic theory of the present control scheme. The validity of the theoretical method and the choice of optimal pulse parameters are discussed in Sect. 5.3. In Sect. 5.4 we provide several numerical examples i) complete electronic excitation of the wavepacket from a nonequilibrium displaced position, taking LiH and NaK as examples ii) pump-dump and creation of localized target wavepackets on the ground electronic state potential, using NaK as an example, and iii) bond-selective photodissociation in the two-dimensional model of H2O. A localized wavepacket is made to jump to the excited-state potential in a desirable force-selective region so that it can be dissociated into the desirable channel. Future perspectives from the author s point of view are summarized in Sect. 5.5. 

For triatomic molecules, the contribution of hot bands cannot be expressed as a function of energy alone (see (5)) and therefore cannot be expressed in a compact analytic formula like Formula (C.3). However, for rigid triatomic molecules like CO2, NO2, SO2, O3 and N2O, the contribution of hot bands is weak at room temperature (and below) because hco kT for all normal mode frequencies. Note that the width of the contribution to the Abs. XS associated with each excited vibrational level (hot bands) is proportional to the slope of the upper FES along the normal mode of the ground electronic corresponding to each excited (thermally populated) vibrational level. This fact explains why numerical models (e.g. using ground state normal coordinates) are able to calculate the Abs. XS. These calculations are of Frank-Condon type. 

In the preceding subsection, the interference effects between nuclear WPs of DCP were numerically treated. In this subsection, to confirm the interference effects, we present the results of an analytical treatment in a simplified one-dimensional model shown in Fig. 6.10. Here, q is the dimensionless normal coordinate of the effective breathing mode. The potentials in the ground and two electronic excited states (b and c, which correspond to L and H, respectively) were assumed to be displaced and undistorted ones. At least two vibrational eigenstates in each electronic state are needed for consideration of both the electronic and vibrational coherences in the simplified model. Here, b0(c0) and bl(cl) denote the lowest... 

All of the physical measurments point to the equivalence of all the platinum atoms (in a noninteger oxidation state) in a chain. The results of the numerous measurements on K2Pt(CN)4Bro.3(H20)s, demonstrates this system to be a one-dimensional metal undergoing a metal-insulator transition as the temperature is lowered. The far infrared and optical measurements show that the electronic excitation spectrum is not that of a simple one-dimensional metal but has a complex behavior at low frequencies. The available data from many diverse types of experiments have been analyzed in terms of numerous models. This system is currently best characterized in terms of a one-dimensional metal undergoing a Peierls transition to a semiconductor at low temperatures, with evidence for the presence of a pinned charge density wave. Further careful measurements of the partially oxidized tetracyanoplatinates are necessary to fully understand the applicability of various one-dimensional models to this class of materials. 

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