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This is an abstract for a poster to be presented at the Fifth Foresight Conference on Molecular Nanotechnology. There will be a link from here to the full article when it is available on the web.

Quantum mechanical investigations of the stability of empty fullerene C_{20+2n} (n=3D 0, 2, 3, ..., 16) molecule isomers with the highest symmetry and the corresponding endohedral fullerene cages with twenty eight encapsulated atoms: even valence : Be, C, O, Mg, Al, Si, S, Zn, Ge, Se, Cd, Sn, Te, Hg, Pb and odd valence : H, N, F, P, Cl, Ga, As, Br, In, Sb, Tl, Bi were performed using the point set group theory in the framework of semiempirical MOPAC-PM3 method [1].

The quantum mechanical investigations of fullerene C_{24}, C_{26}, C_{28} molecule conformers are performed in the framework of point set group theory and semiempirical PM3 configuration interaction, MNDO, AM1 and ab initio SCF/UHF methods. The main criterion of stability of calculated fullerene molecules we state the lowest total energy of various isomers and conformers that appears due to the Jahn-Teller distortion. The most stable occurs C_{24} D_{6} symmetry conformation with term =13EMBED Equation.2 =14=01=15 = and open shell C_{26} D_{3h} symmetry conformation with term =13EMBED Equation.2 =14= =01=15 [2].

The stability and geometry of clathrates C_{60} + CS_{2} were investigated by using PM3 and ab initio SCF/RHF methods It were founded two stationary points of these derivatives during geometry optimization procedure. The quantum chemical calculations and investigations of the stability of twenty eight photoactive charge transfer supramolecules constructed from disc-like pentayne (pentakis(phenyle thynyl)phenyl) molecules with radicals R =3D -OC_{5}H_{11}, -CH_{3}, -CF_{3}, -CN and seven organic electron acceptor molecules: TNF, TeNF, TCNQ, TN_{9}(CN)_{2}F, TCNB, TeClBQ, TeFTCNQ were performed using the MOPAC-PM3 method. All supramolecules have relatively small energetic gap, i. e. they are good electron donors and good electron acceptors at the same time. Therefore these supramolecules should be molecular photodiodes. Energies of formation are largest for supramolecules constructed from disc-like pentayne with -CH_{3} radical and TeNF or TN_{9}(CN)_{2}F molecules - 2.16 and 2.20 kcal/mol respectively. It was founded that: a) all investigated supramolecules: disc-like pentayne molecules::electron acceptor molecules are stable, possess dipole moments and are potential molecular photodiodes; b) the oron donor, electron insulator, electron acceptor and fullerene molecules [1, 3-5].

Complete set of sixteen MIs of two variable logic functions (for example: OR, AND, Implication, Equivalence, Difference, etc.) was designed and also proposed using MIs of two variable molecular logic function initial basic sets: {OR, AND, Negation} or {NOR} and, or {NAND}. We have described in more detail the designed MIs of: a) two variable logic functions OR, NOR, AND, NAND (two sets: one designed from planar molecules and another - from fullerene molecules) , Converse Unitary Negation-1, Converse Unitary Negation-0, Unitary Negation-1, Unitary Negation-0, "0" and "1" Matrix= Constants; b) three variable logic functions AND, NAND, OR, NOR analogs; c) four variable logic functions OR, NOR, AND, NAND analogs, d) molecular cell that simulates one of Life figures, e) summator of neuromolecular network that simulates sigmoidal behaviour of artificial neurone. This was done based on quantum chemical investigations of organic photo-induced electron donor molecules: a) carbazole, 3,6-dibromcarbazole, TeMePhDA, PhDA; b) electron acceptor molecules: TCNQ, TCNB, TeClBQ, small empty and endohedral fullerene molecules: C_{60}, C_{28}, C_{28}H_{4}, C_{24}H_{2}, C_{20}, C_{20}H_{6}, A@C_{60}, A=3DBe, Zn, Cd and c) electron insulator molecules.

[1] Tamulis A., Stumbrys E., Tamulis V. and Tamuliene, J., "Quantum Mechanical Investigations of Photoactive Molecules, Supermolecules, Supramolecules and Design of Basic Elements Molecular Computers", accepted: NATO ASI series, High Technology; Vol. 9, Ed. by F. Kajzar, V.M. Agranovich and C.Y.-C. Lee, "Photoactive Organic Materials: Science and Applications", June 25-30, 1995, Avignon, France, Kluver Academic Publishers, Doderecht/Boston/London, 1996, p.p. 53-66.

[2]. Balevicius L.M., Stumbrys E., Tamulis A., "Conformations and Electronic Structure of Fullerene C_{24} and C_{26} Molecules", Fullerene Science and Technology, accepted for publication 1997, vol. 5, No. 1.

[3] Tamulis, A., Tamulis, V., "Molecular Electronics : Advanced Technology", Science and Arts of Lithuania, 1994, vol. 2, No 4, p.p. 40-47, (in Lithuanian).

[4] Tamulis A., Tamulis V., (1995) "Quantum Mechanical Design of Basic Elements of Molecular Computers", accepted: "#8 Newsletter of International Society of Molecular Electronics and BioComputing", 13 pages,4 figures.

[5] Tamulis A., Braga M., Klimkans A., "Quantum Chemical Investigation of Two Fullerene C_{60} Molecules", Fullerene Science and Technology, 1995, vol. 3, No. 5, p.p. 603-610.

*Corresponding Address:

Dr. Arvydas Tamulis,senior research fellow Institute of Theoretical Physics and Astronomy, Laboratory of Theoretical Molecular Electronics

A. Gostauto 12, Vilnius 2600, Lithuania

Home address: DIDLAUKIO 27-40, Vilnius 2057, Lithuania

tel#: work +(370-2)-620861 or home +(370-2)-778743; fax#: +(370-2)-224694 or +(370-2)-225361; e-mail: TAMULIS@ITPA.LT or GICEVIC@ITPA.LT

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