We report generation of tunable VUV radiation in the range 117-150 nm by four-wave difference-frequency mixing of a tunable ArF excimer laser with an Nd:YAG-pumped dye laser. The four-wave mixing occurs through two-photon resonant enhancement of X((3)) through the E,F(1)Sigma(g)+ (E,' = 2, J' = 0-3) state(s) of H(2) or the 4p(5)6p(3/2)(2) state of Kr in the process (2omega(193) - omega(dye) = omega(VUV)). An estimate of energy efficiency yields 3 x 10(-5) near 133 nm for both H(2) and Kr. Even though several rotational resonances fall within the natural 193-nm bandwidth, mixing with broadband ArF output in H(2) yields single-line VUV output with a FWHM of 3.5 cm(-1) at half the efficiency compared with that of line-narrowed operation.