Measuring aluminum with adsorbed molecular chlorine

　The work function increased by 0.28 eV when the aluminum surface was exposed to air containing 1.34 ppm of chlorine gas for 20 seconds. This is believed to be due to the adsorption of chlorine molecules at the aluminum surface, which changes the work function of aluminum.

Fig.1 Example of work function measurement of
aluminum (Al) before and after spraying with chlorine gas.