Coherent states experimental results

Results for CO/Cu(001) were obtained with a model of electronic and vibrational transitions we have previously derived, with populations and quantum coherences calculated to compare with experimental results from femtosecond spectroscopy and time-of flight measurements. The present results show that the populations of individual vibronic states oscillate as a result... 

Abstract. New direct observation data on the 2S-2P atomic states coherent mixing upon hydrogen atoms passage through a metal-wall slit are presented. The experimental results axe interpreted in terms of atomic states interference. 

A coherent interpretation for many experimental results was provided by the concept of a PS I reaction centre. This centre has now been isolated, albeit perhaps not in a definitely pure state. It is made up of a few hydrophobic polypeptides, the primary donor (P-700), several electron acceptors (Fig. 2), and about 50 molecules of pigment (chlorophyll a and /3-carotene). This composition is analogous to that of other types of reaction centres. 

The equality sign holds if the radiation results from a transition between two pure atomic states, such as a transition. Then the radiation is said to be completely coherent. An experimental measurement of P or p allows us to obtain some information on the coherence properties of the excitation process. 

The coherent motion initiated by an excitation pulse can be monitored by variably delayed, ultrashort probe pulses. Since these pulses may also be shorter in duration than the vibrational period, individual cycles of vibrational oscillation can be time resolved and spectroscopy of vibrationally distorted species (and other unstable species) can be carried out. In the first part of this section, the mechanisms through which femtosecond pulses may initiate and probe coherent lattice and molecular vibrational motion are discussed and illustrated with selected experimental results. Next, experiments in the areas of liquid state molecular dynamics and chemical reaction dynamics are reviewed. These important areas can be addressed incisively by coherent spectroscopy on the time scale of individual molecular collisions or half-collisions. 

Section III deals with spatial phenomena. The current state of theoretical description is given in Section in.l, and experimental results are compiled in Section III.2. The organization of these two parts is analogous to Section II, that is, first waves in bistable media are discussed and then pattern formation in oscillatory media. Because the investigations of spatial self-organization are still in their infancy, not all theoretical predictions have yet been experimentally verified, and many experiments cannot yet be understood in terms of the underlying physical mechanisms. Hence this section represents a first approach toward a coherent imder-standing of spatial stractures, and a series of open questions is hsted at the end. 

In short, the experimental results presented above collectively form a more coherent understanding of the [Mn(salen)] -catalyzed epoxidation of unfunctionalized olefins. Side-on approach of the substrate at the metal-oxo species leading to stepwise C-0 bond formation offers a straightforward explanation for product selectivity and additive effects. The degree of C-0 bond formation reflects the position of the transition state along the reaction coordinate, and it is this position that is critical to the level of asymmetric induction in the [Mn(salen)]-catalyzed epoxidation. 

Abstract We review the basic theoretical formulation for pulsed X-ray scattering on nonstationary molecular states. Relevant time scales are discussed for coherent as well as incoherent X-ray pulses. The general formalism is applied to a nonstationary diatomic molecule in order to highlight the relation between the signal and the time-dependent quantum distribution of intemuclear positions. Finally, a few experimental results are briefly discussed. 

Biological luminescence is explained by quantum coherence theory assuming that the radiative field is an odd and even coherent field. The radiant intensity curve versus time of biophoton emission agrees with the experimental results. Hence, biophotons arise from a non-classical state radiant field, and the parameter k is also related to the biological characteristics the decay time is shortened with an increasing in k, i.e., it can control the velocity of biophoton emission. 

We shall presently describe the derivation of certain coherent excitations on the basis of definite physical models. Such developments show that random energy supplied to a certain system need not lead to heating but may result in the excitation of ordered (coherent) states. This need not imply that other models could not lead to similar excitations, i.e., that a multicausal situation exists— in other words that experimental verification of the excitation need not necessarily be considered as proof of a particular model. Clearly a situation then arises which requires close collaboration between theory and experiment. Thus, e.g., theory has predicted certain coherent excitations and experiment verifies their existance. This presents a development from the point of view of physics. From the point of view of biology, however, we may ask a question that is prohibited in physics what is the purpose of these excitations Evidence will be presented later in this chapter for the first (physical) stage, but the second, biological question has hardly been touched yet. Its solution will, of course, lead back again to physics, i.e., a certain process has certain consequences. 

The first example is a three-level A-type system coupled by bichromatic coupling and probe fields, which opens two Raman transition channels [60]. The phase dependent interference between the resonant two-photon Raman transitions depends on the relative phases of the laser fields either constructive interference or destructive interference between the two Raman channels can be obtained by controlling the laser phases. The second example is a four-level system coupled by two coupling fields and two probe fields, in which a double-ElT configuration is created by the phase-dependent interference between the three-photon and one-photon excitation processes, or equivalently two independent Raman transition channels [58,62]. We will provide theoretical analyses of the phase dependent quantum interference in the two multi-level atomic systems and present experimental results obtained with cold Rb atoms. The two systems provide basic platforms to study coherent atom-photon interactions and quantum state manipulations, and to explore useful applications of the phase-dependent interference in the multi-level atomic systems. 

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