Infrared absorption spectra of dimethyl ether (DME) and methanol mixtures were recorded in solid argon matrix at 9 K. A number of intramolecular complex bands were observed both in the DME and methanol fundamental regions. From the concentration dependence of infrared spectral patterns, DME and methanol seemed to form at least two types of 1:1 binary complexes. Referring to the ab initio SCF, MP2, and DFT level computations, the most stable complex was concluded to possess a trans near linear H-bond, formed between the ethereal oxygen and the hydroxyl hydrogen atoms. The next stable 1:1 DME-methanol complex was proposed to assume a geometry with a I-I-bond angle to be at ca. 150 degrees. (C) 1999 Elsevier Science B.V. All rights reserved.