Usually the stretching vibration of the A-H group in hydrogen-bonded complexes gives an intense, broad absorption in the IR spectrum. However in a few complexes it has proved difficult to detect this absorption in low temperature matrices. In this work the Ratajczak-Yaremko vibrational model of the hydrogen bond has been applied to simulate the IR spectrum obtained for one such complex: the pentachlorophe nol-trimethylamine, PCP-TMA, hydrogen bonded complex isolated in an argon matrix. Quantum chemical calculations have also been carried out to gain further insight into this complex. (C) 2016 Elsevier B.V. All rights reserved.