Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Surface-wave discharges in argon at atmospheric pressure were experimentally studied by optical emission spectroscopy (OES) and mass spectrometry (MS). OES was employed to determine the rotational temperature using the ultraviolet OH band, Q(1) branch and found to be between 450 and 970 K. The electron density (5 x 10(13) cm(-3) <= n(e) <= 7 x 10(14) cm(-3)) was estimated using the H-beta line profile, and produced by dissociation of the water present as an impurity in the Ar gas. The electron temperature (0.63 eV <= T-e <= 1.3 eV) was estimated using a collisional-radiative (CR) model that takes the input measured intensities of four emission lines originating from 2p states including 2p(2), 2p(4), 2p(6), and 2p(10). The density of the metastable state Ar(1s(5)) (2.0 x 10(11) cm(-3) <= Ar(1s(5)) <= 4.2 x 10(12) cm(-3)) was estimated by means of OES using the self-absorbing method. Positive and negative ions were probed along the plasma column using MS. A theoretical model based on the solution of the homogeneous electron Boltzmann equation, considering inelastic and superelastic collisions with the Ar(1s) states and electron-electron collisions, coupled with a system of rate balance equations describing the creation and destruction of the most important heavy particles, is proposed. The experimental results are compared with theoretical ones obtained from a self-consistent model of these discharges, providing physical insight into the basic mechanisms and phenomena ruling the discharges.577 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundacao para a Ciencia e a Tecnologia (FCT) [Pest-OE/SADG/LA0010/2013]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2008/58034-0]