Abstract:A computer program based on the Frame method for the characteristic polynomials of graphs is developed. This program makes use of an efficient polynomial algorithm of Frame for generating the coefficients in the characteristic polynomials of graphs. This program requires as input only the set of vertices that are neighbors of a given vertex and with labels smaller than the label of that vertex. The program generates and stores only the lower triangle of the adjacency matrix in canonical ordering in a one-dimen… Show more
“…Second, graph-theoretical pruning procedures such as the ones described in the present author's papers [30,35] can be employed to simplify the Hamiltonian. The characteristic polynomials of the associated graphs [32] could be very valuable for the generation of properties such as spectral moments, walks on weighted graphs [33], etc. Many important properties of the associated compounds can be generated from the spectral moments.…”
Section: Graph-theoretical Formulation Of the Ppp Methodsmentioning
Two different color-related applications of the Pariser-Pam-Pople method are described. The first one deals with an explanation of the uv-visible absorption spectrum of the curcumin pigment in turmeric and the color change of curcumin upon addition of OH-. The other application deals with blue and red shifts in poly-diacetylene to polybutatriene transformation. The applications of the FEMO and PPP methods to curcumin facilitate assignment of the two observed bands of curcumin (UV and visible) to the r + r* (uv) and n + r* (visible) transitions, respectively. A graph-theoretical formulation of the PPP method is also considered.
“…Second, graph-theoretical pruning procedures such as the ones described in the present author's papers [30,35] can be employed to simplify the Hamiltonian. The characteristic polynomials of the associated graphs [32] could be very valuable for the generation of properties such as spectral moments, walks on weighted graphs [33], etc. Many important properties of the associated compounds can be generated from the spectral moments.…”
Section: Graph-theoretical Formulation Of the Ppp Methodsmentioning
Two different color-related applications of the Pariser-Pam-Pople method are described. The first one deals with an explanation of the uv-visible absorption spectrum of the curcumin pigment in turmeric and the color change of curcumin upon addition of OH-. The other application deals with blue and red shifts in poly-diacetylene to polybutatriene transformation. The applications of the FEMO and PPP methods to curcumin facilitate assignment of the two observed bands of curcumin (UV and visible) to the r + r* (uv) and n + r* (visible) transitions, respectively. A graph-theoretical formulation of the PPP method is also considered.
The resulting polynomials are then assembled to compute the matching polynomial of the initial graph. The program is especially useful in generating the matching polynomials of graphs containing a large number of vertices. The matching polynomials thus generated are potentially useful in several applications such as lattice statistics (dimer covering problem), aromaticity, valence bond methods (enumeration of perfect matchings) in the calculation of grand canonical partition functions, in the computation of thermodynamic properties of saturated hydrocarbons, and in chemical documentation.
“…Polyene molecules with 8, 9, or 10 carbon vertices can be determined also if one or more eigenvalues are known via embedding or by its alternant or symmetry characteristics (2,3). The method presented in this paper expands the scope of those previously published (4)(5)(6).…”
Section: [L] a 4 = ( 1 / 2 ) ( Q 2 -9 Q + 6 N C ) -2 R 4 -D L -D 4 -3mentioning
JERRY RAY DIAS. 1987. Can. J. Chem. 65, 734 (1987. Determination of common eigenvalues by embedding smaller subgraphs onto larger ones is illustrated. A nearly universal expression of the sixth coefficient of the characteristic polynomial valid for all conjugated hydrocarbon polyenes is presented. Its use in a graph theoretical determination of the Huckel MO characteristic polynomial of molecular graphs possessing heteroatoms is detailed.JERRY RAY DIAS. 1987. Can. J. Chem. 65, 734 (1987 On illustre comment on peut determiner les valeurs propres communes en incorporant des petits graphiques dans des plus grands. On prtsente une expression qui est pratiquement universelle pour la determination du sixi&me coefficient du polynome caracttristique qui est valide pour tous les hydrocarbures polytniques conjugts. On prtsente les details de son utilisation dans la determination, dans la thtorie des graphs, du polyn6me caracttristique des OM de Huckel des graphiques moltculaires posstdant des hettroatomes.[Traduit par la revue]
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