Low pressure argon dual-frequency (DF) capacitively coupled plasma (CCP) is generatedby using different frequency configurations,such as 13.56/2,27/2,41/2,and 60/2 MHz.Characteristics of the plasma are investigated by using a floating double electrical probe and opticalemission spectroscopy (OES).It is shown that in the DF-CCPs,the electron temperatureT;decreases with the increase in exciting frequency,while the onset of 2 MHz induces a suddenincrease in T;and the electron density increases basically with the increase in low frequency(LF) power.The intensity of 750.4 nm emission line increases with the LF power in the caseof 13.56/2 MHz,while different tendencies of line intensity with the LF power appear for otherconfigurations.The reason for this is also discussed.