The special features of the formation of molecular ions on the surface of tantalum

Thermal emission of singly charged positive molecular ions, mass 254, from the surface of a tantalum band was studied. Thermal emission appeared if, first, oxygen acted on a tantalum band at a temperature higher than 600°C, and then the band was held at room temperature. At the time of holding t longer than a minute, thermal emission linearly depended on . The special features of thermal emission were explained by the presence of a critical temperature of tantalum close to 400°C, at which all the molecular ions were emitted from the surface. A new model of their formation was suggested.