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F Illas

Publications and source records attributed to F Illas.

At least 19 recordsLinked to original sources
PubMed2000

Accurate prediction of large antiferromagnetic interactions in high- T(c) HgBa2Ca(n-1)Cu(n)O(2n+2+delta) ( n = 2,3) superconductor parent compounds

The in-plane nearest-neighbor Heisenberg magnetic coupling constant, J, of La2CuO4, Nd2CuO4, Sr2CuO2Cl2, YBa2Cu3O6, and undoped HgBa(2)Ca(n-1)Cu(n)O(2n+2+delta) ( n = 1,2,3) is calculated from accurate ab initio configuration interaction calculations. For the first four compounds, the theoretical J values are in quantitative agreement with experiment. For the Hg-based compounds the predicted values are -135 meV ( n = 1) and approximately -160 meV ( n = 2,3), the latter being much larger than in previous cases and, for n = 3, increasing with pressure. Nevertheless, the physics governing J in all these layered cuprates appears to be the same. Moreover, calculations suggest a possible relationship between J and T(c).

Journal Article↗
PubMed1987

On the mechanism of histamine H2 receptor activation.

The H2 receptor activation mechanism model proposed by Weinstein et al. [Mol. Pharmacol. 12:738-745 (1976)] has been considered for the set of H2 agonists. The energetics of the model proton transfer processes from a proton-donor site to the heterocycle ring of the agonist molecule and from this one to a proton acceptor site have been studied by using the semiempirical AM1 and MNDO quantum mechanical methods. The STO-3G ab initio molecular electrostatic potential for each compound in its active form has also been computed. Results show the mechanistic model to be satisfactory and lead to a qualitative and quantitative explanation of the H2 activity data.

Chemical Phenomena↗