Investigation of local work function distribution of field emission cathode from carbon materials doped by Ba with the help of AFM/SEM/X-ray

Sherstnev, P.V.; Baturin, A. S.; Бормашов, В. С.; Nikolski, K.N.; Sheshin, E.P.

doi:10.1016/j.jpcs.2003.10.010

Cited by 2 publications

(1 citation statement)

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“…On the other hand, it was reported previously that many properties pertaining to large polynuclear aromatics must approach those of graphite at its largest size limit. − Among these properties are included the ionization energy and electron affinity, both of which are expected to approach the work function of graphite. However, in the case of linear polyene-conjugated systems, no previous reports exist that are focused on clarifying how various properties observed in graphite differ from those of smaller molecules.…”

Section: Introductionmentioning

confidence: 99%

Donator−Acceptor Map and Work Function for Linear Polyene-Conjugated Molecules. A Density Functional Approximation Study

Martı́nez

2009

J. Phys. Chem. B

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Carotenoids are one particular type of conjugated chromophores with a great capacity for accepting electrons. The question posed here is how the capacity to accept electrons is related to extension of the conjugation. If there is a connection, any chromophore should represent a good antiradical, a point of interest for those investigating the biological effects of antioxidants. In order to analyze the relationship between the extension of the conjugation and the absorbance and electron-donor properties described in this paper, full geometry optimizations at the BPW91/D5DVZ level of theory are reported for a number of linear conjugated polyene systems. Maximum wavelengths were obtained using the TDDFT methodology. From these results, it is possible to conclude that large conjugated chromophores have a great capacity for accepting electrons but diminished power for donating electrons. Apparently, any chromophore should be a good antiradical, but various mechanisms exist for scavenging free radicals. In the case of linear polyene-conjugated molecules, indigo, blue, and green chromophores represent good antiradicals because they are also good antioxidants (effective electron donors). Yellow and red chromophores represent good antiradicals because they are good antireductants (effective electron acceptors). In the case of the molecules reported in this paper, the ionization energy and the electron affinity come close to the work function of graphite. This may be important for future applications, where the movement of the electrons is crucial.

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