The reason why aurum is more noble than argentum according to density functional theory calculations.

Aurum and argentum are the most useful metal of all the minerals mined from the Earth. Both of them are noble metal. This research verify the aurum's nobleness compared with argentum based on the adsorption energy of hydrogen atom on the metal surfaces. The adsorption energy can be obtained by studying a simple surface reaction, the adsorption of molecule hydrogen on the metal surfaces. The calculation of adsorption energy was done computationally based on Density Functional Theory. This research found that aurum has the most positive adsorption energy compared with argentum. The more positive the adsorption energy, the harder it will be for hydrogen atom to adsorp to the surface. This result indicates that aurum is more noble than argentum. [ABSTRACT FROM AUTHOR]