title: Spectroscopic characterization of  van der Waals interactions in a metal organic framework with unsaturated metal centers: MOF-74-Mg.
abstract: The adsorption energies of small molecules in nanoporous materials are often determined by isotherm measurements. The nature of the interaction and the response of the host material, however, can best be studied by spectroscopic methods. We show here that infrared absorption and Raman spectroscopy measurements together with density functional theory calculations, utilizing the novel van der Waals density functional vdW-DF, constitute a powerful approach to studying the weak van der Waals interactions associated with the incorporation of small molecules in these materials. In particular, we show how vdW-DF assists the interpretation of the vibrational spectroscopy data to uncover the binding sites and energies of these molecules, including the subtle dependence on loading of the IR asymmetric stretch mode of CO(2) when adsorbed in MOF-74-Mg. To gain a better understanding of the adsorption mechanism of CO(2) in MOF-74-Mg, the results are compared with CO within MOF-74-Mg.
authors.affiliation: Department of Materials Science and Engineering, University of Texas at Dallas, TX 75080, USA.
authors.forename: Nour
authors.initials: N
authors.lastname: Nijem
authors.forename: Pieremanuele
authors.initials: P
authors.lastname: Canepa
authors.forename: Lingzhu
authors.initials: L
authors.lastname: Kong
authors.forename: Haohan
authors.initials: H
authors.lastname: Wu
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Timo
authors.initials: T
authors.lastname: Thonhauser
authors.forename: Yves J
authors.initials: YJ
authors.lastname: Chabal
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D008274:Magnesium / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D011789:Quantum Theory; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D014732:Vibration
chemical_list: D009942:Organometallic Compounds; D002245:Carbon Dioxide; D008274:Magnesium