Halogen bonding interaction (X-Bond) is prevalent over hydrogen bonding (H-Bond) interaction in [CH₃OH–CCl₄] mixtures/clusters: consequence in polar/non-polar mixtures and/or corresponding complexes in atmosphere needs to be investigated.

Se is now considered as a potential centre for hydrogen bond interactions. The hydrogen bond acceptor ability of Se has been investigated in [ROH–Se(CH₃)₂] complexes (R = H, CH₃, and C₂H₅) using matrix-isolation infrared spectroscopy and electronic structure calculations. The first impression of the IR spectra of the hydrogen bond complexes of [ROH–Se(CH₃)₂] in N₂ and Ar matrices is presented here. Moreover, no spectroscopic data are available for the [HOH–Se(CH₃)₂] complex. Vibrational spectra in the OH stretching region indicate the formation of the [ROH–Se(CH₃)₂] complex under the matrix-isolation conditions. Comparison of the experimental spectra with the simulated vibrational frequencies at different levels of theory confirms the formation of the 1 : 1 cluster of [ROH–Se(CH₃)₂] stabilised by O–H⋯Se hydrogen bond interactions. Multiple conformers of the [CH₃OH–Se(CH₃)₂] complex having marginally different stabilisation energies have been predicted from electronic structure calculations and signatures of the same have been observed under the cold conditions of matrix isolation. Conformer specific assignment of the 1 : 1 cluster of [C₂H₅OH–Se(CH₃)₂] (anti and gauche forms) has been carried out in both the matrices. Concentration dependent experiments indicate the formation of higher order clusters and/or mixed clusters along with the formation of a 1 : 1 cluster for CH₃OH and C₂H₅OH. The nature of the selenium centred hydrogen bond has been delineated using AIM, NBO and energy decomposition analysis. A comparison of similar complexes of H₂O, CH₃OH, and C₂H₅OH with O, S and Se indicates that Se is not far away in hydrogen bond acceptor ability compared to O and S.

The (X=Cl, Br, and I) complexes have been studied to understand the tendency towards the formation of hydrogen bonds and halogen bonds. Three different types of interactions viz., C–X O, C‐H O, and O‐H X, are possible between the and . Experiments have been carried out in low temperature matrix using Fourier Transform Infrared spectroscopy. Electronic structure calculations have been performed to identify the possible binding motifs between and . Formation of more than one complex has been confirmed in (X=Br and I) mixture, using the experimental and simulated IR spectra, whereas only one type of complex is found in mixture. Energy decomposition analysis, quantum theory of atoms in molecules, and non‐covalent interaction analysis have been performed to understand the nature of interaction and the driving force for complexation under experimental conditions.