Author/Authors :
Radhika Devi، نويسنده , , V. and Shrivastava، نويسنده , , Keshav N.، نويسنده ,
Abstract :
Density functional theory is used to optimize hexagons of all the atoms from the atomic number 1–103. It is found that the hexagon bond length oscillates as one goes along the periodic table. These oscillations can be understood in terms of the electronic structure. A molecule of hydrogen is adsorbed on the surface of group II atoms Be, Mg, Ca, Sr, Ba and Ra. The adsorption energy is the largest for Be and decreases in going from Be to Sr but increases for Ba. The hexagonal bond length increases from 2.24 Å for Be to 4.4 Å for Ra. Similarly, adsorption of hydrogen molecule on surfaces of rare gas atoms He, Ne, Ar, Kr, Xe and Rn has been optimized. The adsorption energy varies from 0.048 ev for He to 0.025 ev for Rn. Adsorption of hydrogen molecule is also obtained successfully on chalcogens O, S, Se, Te and Po and discussed. Here the adsorption energy is largest for O and smallest for Po. In this way the adsorption of hydrogen molecule on surfaces of 22 different atoms is successfully obtained.