Enantiomer Control Oriented Molecules

An alternative way to introduce chirality into the interaction of matter with using linearly polarized light has been introduced by Fujimura et al. [263, 264 this approach one first preorients the racemic mixture of D and L along 

To appreciate the essence of this control scenario, recall the results of applying a laser pulse a(t) to induce a transition between two bound states Ef) and , ). We denote the dipole transition matrix element between these two states by d,- - and define k,j = 2d j/ti. Then it is well known [279] that complete population transfer between these levels can be accomplished by using a n pulse, that is, a pulse of duration t satisfying 

16 Model system for enantiomer control in accord with Ref. [264]. Notation is such pfiat jgnR) denotes the D enantiomer on the ground electronic state in vibrational state n, gtiL) l thte analogous state of the L enantiomer and em) is the th level of excited electronic state. 

Section 8.2 requires the computation of the B-A B photodissociation elements in Eq. (8.12). To cariy out this computation, and to understand 1 origin of the loss of control with m averaging, we sketch the details of the forma for the model HaOHfc system. 

it is necessary to specify the relevant n and i quantum numbers that e the bound-free matrix elements (E, n, q deg Ej). For the continuum n = [k, vj, m) where k is the scattering direction, v and j are the vibrationaf rotational product quantum numbers and m is the space-fixed z projection of/yl 

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Nonpolar and dipolar altitudinal rotors (compounds 2 and 3 in Fig. 17.3) have been synthesized. 19F NMR spectroscopy showed that the barrier to rotation in 3 was extremely low in solution. Both systems have then been immobilized on Au(l 11) surfaces and studied with a variety of techniques.57 The results obtained indicated that for a fraction of molecules the static electric field from the scanning tunneling microscopy (STM) tip could induce an orientation change in the dipolar rotor but not in the nonpolar analog (for a recent example of an azimuthal molecular rotor controlled by the STM tip, see Reference 58). Compound 3 can exist as three pairs of helical enantiomers because of the propeller-like conformation of the tetra-arylcyclobutadienes. For at least one out of the three diastereomers, an asymmetric potential energy surface can be predicted by molecular dynamics simulations on application of an alternating electric field.55... 

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