D-states

Mulliken symbols The designators, arising from group theory, of the electronic states of an ion in a crystal field. A and B are singly degenerate, E doubly degenerate, T triply degenerate states. Thus a D state of a free ion shows E and Tj states in an octahedral field. 

Ultraviolet photoelectron spectroscopy (UPS) results have provided detailed infomiation about CO adsorption on many surfaces. Figure A3.10.24 shows UPS results for CO adsorption on Pd(l 10) [58] that are representative of molecular CO adsorption on platinum surfaces. The difference result in (c) between the clean surface and the CO-covered surface shows a strong negative feature just below the Femii level ( p), and two positive features at 8 and 11 eV below E. The negative feature is due to suppression of emission from the metal d states as a result of an anti-resonance phenomenon. The positive features can be attributed to the 4a molecular orbital of CO and the overlap of tire 5a and 1 k molecular orbitals. The observation of features due to CO molecular orbitals clearly indicates that CO molecularly adsorbs. The overlap of the 5a and 1 ti levels is caused by a stabilization of the 5 a molecular orbital as a consequence of fomiing the surface-CO chemisorption bond. 

You can use Cl to predict electronic spectra. Since the Cl wave function provides groun d state an d excited state energies, you can obtain electron ic absorption frequen cies from the dlfferen ces between the energy of the ground state and the excited states. 

The Microstate Cl Method lowers the energy of the tin correlated groun d state as well as excited states, fhe Sngly Eixcitecl Cl Method is particularly appropriate for calculating LIV visible spectra, and does not affect the energy of the ground state (Brillouin s fheo-rem). 

Hor trail sitlon m ctal comp lexes with several possible spin arrangements, a separate calculation within each spin multiplicity m ay be required to find th e groiin d state of the com plex. 

Brooks, B.R. Bruccoleri, R.E. Olafson, B.D. States, D.J. Swaminathan, S. Karpins, M. CHARMM A program for macromolecular energy, minimization, and dynamics calculations J. Comput. Chem. 4 187-217, 1983. 

Figure 7.20(b) illustrates the case where r c r". An example of such a transition is the Mulliken band system of C2 (see Table 7.6 and Figure 7.17). The value of is 1.2380 A in the D state and 1.2425 A in the X state. Here the most probable transition is from A to B with no vibrational energy in the upper state. The transition from A to C...

Using this model in analogy with previous studies we can calculate a magnetic moment (fi) of the system with fixed Stoner exchange parameter Id and occupation of the d states. The total energy could then be calculated as the balance between the kinetic energy and the spin-polarization energy ... 

Tributsch H (1982) Photoelectrochemical Energy Conversion Involving Transition Metal d-States and Intercalation of Layer Compounds. 49 127-175 Truter MR (1973) Structures of Organic Complexes with Alkali Metal Ions. 16 71-111 Tytko KH, Mehmke J, Kurad D (1999) Bond Length-Bond Valence Relationships, With Particular Reference to Polyoxometalate Chemistry. 93 1-64 Tytko KH (1999) A Bond Model for Polyoxometalate Ions Composed of M06 Octahedra (MOk Polyhedra with k > 4). 93 65-124... 

Our representation of a metal is shown in Fig. 6.18. It possesses a block-shaped, partly filled sp band behaving as a free electron gas and a d band that is filled to a certain degree. The sp band is broad as it consists of highly delocalized electrons smeared out over the entire lattice. In contrast, the d band is much narrower because the overlap between d states, which are more localized on the atoms, is much smaller. 

In this section we summarize the main results in simple and idealized schemes. We consider adsorption on a free electron metal, and on a transition metal. In particularly the adsorption of a molecule on a metal with d states is of great interest for catalysis. 

The adsorbate-covered clusters yield a UPS difference spectrum with two peaks on either side of the metal d-states. The dominant changes in the intensity ratio of these peaks occur up to 50-atom Ag clusters which can be rationalized in terms of the cluster d band width and IP, which both depend on cluster size. 

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