A technique of time going backwards is used to simulate the deposition of ozone molecules mixed with argon atoms from the gas phase onto a cold surface. The relative probabilities of various trapping sites are obtained at different deposition temperatures (5, 10, and 20 K). Single substitutional sites are probably formed the most and they can be grouped into two subsites, specified by the doublet frequency splitting of the upsilon(3) mode acquired via the normal mode calculation of O-3 in the matrix. The probability ratio of the two subsites depends upon the deposition temperatures. The normal frequencies of O-3 calculated in double-, triple-, and multiple-substitutional sites distribute over a wide range, implying that they are not easily observable sites in an infrared spectrum. A series of experimental observations are interpreted well with the above calculations.