Zang et al. later experimentally confirmed this effect using scanning tunneling microscope break-junction measurements. They synthesized and studied a series of cumulenes and polyynes ranging from 4 to 8 carbon atoms. These molecules were functionalized with thiomethyl groups to form junctions with gold electrodes. The measurements showed that while polyynes exhibited the expected exponential decay in conductance, cumulenes displayed the opposite trend, increasing their conductance with molecular length.