Old Dominion University ODU Digital Commons Chemistry & Biochemistry Faculty Publications Chemistry & Biochemistry 12-2017 Molecular Geometries and Other Properties of H2O⋯AgI and H3N⋯AgI as Characterised by Rotational Spectroscopy and ab initio Calculations Chris Medcraft Eva Gougoula Dror M. Bittner Old Dominion University John C. Mullaney Susana Blanco See next page for additional authors Follow this and additional works at: https://digitalcommons.odu.edu/chemistry_fac_pubs Part of the Biochemistry Commons, and the Chemistry Commons Repository Citation Medcraft, Chris; Gougoula, Eva; Bittner, Dror M.; Mullaney, John C.; Blanco, Susana; Tew, David P.; Walker, Nicholas R.; and Legon, Anthony C., "Molecular Geometries and Other Properties of H2O⋯AgI and H3N⋯AgI as Characterised by Rotational Spectroscopy and ab initio Calculations" (2017). Chemistry & Biochemistry Faculty Publications. 98. https://digitalcommons.odu.edu/chemistry_fac_pubs/98 Original Publication Citation Medcraft, C., Gougoula, E., Bittner, D. M., Mullaney, J. C., Blanco, S., Tew, D. P., . Legon, A. C. (2017). Molecular geometries and other properties of H2O⋯AgI and H3N⋯AgI as characterised by rotational spectroscopy and ab initio calculations. The Journal of Chemical Physics, 147(23) 234308. doi:http://dx.doi.org/10.1063/1.5008744 This Article is brought to you for free and open access by the Chemistry & Biochemistry at ODU Digital Commons. It has been accepted for inclusion in Chemistry & Biochemistry Faculty Publications by an authorized administrator of ODU Digital Commons. For more information, please contact [email protected]. Authors Chris Medcraft, Eva Gougoula, Dror M. Bittner, John C. Mullaney, Susana Blanco, David P. Tew, Nicholas R. Walker, and Anthony C. Legon This article is available at ODU Digital Commons: https://digitalcommons.odu.edu/chemistry_fac_pubs/98 Molecular geometries and other properties of H2O#AgI and H3N#AgI as characterised by rotational spectroscopy and ab initio calculations Chris Medcraft, Eva Gougoula, Dror M. Bittner, John C. Mullaney, Susana Blanco, David P. Tew, Nicholas R. Walker, and Anthony C. Legon Citation: The Journal of Chemical Physics 147, 234308 (2017); View online: https://doi.org/10.1063/1.5008744 View Table of Contents: http://aip.scitation.org/toc/jcp/147/23 Published by the American Institute of Physics Articles you may be interested in Structure, spectroscopy, and dynamics of the phenol-(water)2 cluster at low and high temperatures The Journal of Chemical Physics 147, 234307 (2017); 10.1063/1.5006055 Halogen bonding properties of 4-iodopyrazole and 4-bromopyrazole explored by rotational spectroscopy and ab initio calculations The Journal of Chemical Physics 147, 214303 (2017); 10.1063/1.5002662 Towards a quantum chemical protocol for the prediction of rovibrational spectroscopic data for transition metal molecules: Exploration of CuCN, CuOH, and CuCCH The Journal of Chemical Physics 147, 234303 (2017); 10.1063/1.5006931 - Channel branching ratios in CH2CN photodetachment: Rotational structure and vibrational energy redistribution in autodetachment The Journal of Chemical Physics 147, 234309 (2017); 10.1063/1.5001475 The reactivity of the Criegee intermediate CH3CHOO with water probed by FTMW spectroscopy The Journal of Chemical Physics 148, 014308 (2018); 10.1063/1.5009033 Photodissociation of van der Waals complexes of iodine X–I2 (X = I2, C2H4) via charge-transfer state: A velocity map imaging investigation The Journal of Chemical Physics 147, 234304 (2017); 10.1063/1.5001104 THE JOURNAL OF CHEMICAL PHYSICS 147, 234308 (2017) Molecular geometries and other properties of H2O··· AgI and H3N··· AgI as characterised by rotational spectroscopy and ab initio calculations Chris Medcraft,1 Eva Gougoula,1 Dror M. Bittner,2 John C. Mullaney,1 Susana Blanco,3 David P. Tew,4 Nicholas R. Walker,1,a) and Anthony C. Legon4,a) 1Chemistry-School of Natural and Environmental Sciences, Newcastle University, Bedson Building, Newcastle-upon-Tyne NE1 7RU, United Kingdom 2Department of Chemistry and Biochemistry, Old Dominion University, 4541 Hampton Boulevard, Norfolk, Virginia 23529-0126, USA 3Departamento de Quimica Fisica y Quimica Inorganica, Facultad de Ciencias, Universidad de Valladolid, 47011 Valladolid, Spain 4School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom (Received 9 October 2017; accepted 27 November 2017; published online 20 December 2017) The rotational spectra of H3N··· AgI and H2O··· AgI have been recorded between 6.5 and 18.5 GHz by chirped-pulse Fourier-transform microwave spectroscopy. The complexes were generated through laser vaporisation of a solid target of silver or silver iodide in the presence of an argon gas pulse containing a low concentration of the Lewis base. The gaseous sample subsequently undergoes super- sonic expansion which results in cooling of rotational and vibrational motions such that weakly bound complexes can form within the expanding gas jet. Spectroscopic parameters have been determined for eight isotopologues of H3N··· AgI and six isotopologues of H2O··· AgI. Rotational constants, B0; centrifugal distortion constants, DJ , DJK or ∆J , ∆JK ; and the nuclear quadrupole coupling constants, χaa(I) and χbb(I) χcc(I) are reported. H3N··· AgI is shown to adopt a geometry that has C3v sym- metry. The geometry of H2O··· AgI is Cs at equilibrium but with a low barrier to inversion such that the vibrational wavefunction for the v = 0 state has C2v symmetry. Trends in the nuclear quadrupole coupling constant of the iodine nucleus, χaa(I), of L··· AgI complexes are examined, where L is varied across the series (L = Ar, H3N, H2O, H2S, H3P, or CO). The results of experiments are reported alongside those of ab initio calculations at the CCSD(T)(F12*)/AVXZ level (X = T, Q). Published by AIP Publishing. https://doi.org/10.1063/1.5008744 I. INTRODUCTION spectroscopy has proven to be a powerful tool for inves- tigation of the structure and dynamics in such complexes. Microwave spectroscopy has recently been applied to Previous studies have made comparisons with hydrogen- explore the molecular structures of complexes in which and halogen-bonded complexes of similar geometrical a Lewis base is attached to either CuX, AgX, or AuX structure. (where X is a halogen atom) to form L··· MX,1–11 where, Examination of the trend in the nuclear quadrupole cou- 1,10 3–5 12 6,8,11 for example, L = H2O, H2S, NH3, C2H2, or pling constant of chlorine, χaa(Cl), across the CO.13,14 The same technique has also been applied to study L··· AgCl4,8,10,15,20,21 series revealed that the attachment of complexes that are similar in composition and structure Ar to AgCl19 induces only a very small change in the quan- but distinct in that L is not a typical Lewis base. For tity relative to the value of the parameter in diatomic AgCl. 15,16 17–19 18,20 example, H2··· MX, Ar··· MX, Kr··· MX, and The described change varies with L in the order CO > H2S 21 Xe··· MX have each been characterised. Significant struc- > H3N > H2O. A very similar trend was observed in the 15,16 6,8,11 4,6,10,12 tural changes were identified in each of H2, C2H2, equivalent L··· CuCl series. The variation in χaa(Cl) 6 and C2H4 on their attachment to a coinage metal atom. provides an indication of the extent of electron redistribu- Both H2O··· MX and H2S··· MX adopt pyramidal geome- tion accompanying the formation of each of these complexes. tries of Cs symmetry at equilibrium. H2O··· MX complexes Evidently, stabilisation of OC··· MCl through back-donation were observed to undergo rapid inversion between two of electrons from d orbitals of the metal onto π* orbitals of equivalent Cs geometries on the time scale of a molecu- CO leads to a stronger interaction than that existing within lar rotation such that the geometry of H2O··· MX is effec- Ar··· MCl. The present work aims to determine rotational con- 1,3–5,10,22 tively C2v (planar) in the v = 0 state. Rotational stants, centrifugal distortion constants, and nuclear quadrupole coupling constants of the L··· AgI complexes for which L = H2O or H3N and use these quantities to draw conclusions a)Authors to whom correspondence should be addressed: Nick.Walker@ about the geometries, interaction strength, and electric charge newcastle.ac.uk and [email protected] redistribution associated with the complexes. The results will 0021-9606/2017/147(23)/234308/8/$30.00 147, 234308-1 Published by AIP Publishing. 234308-2 Medcraft et al. J. Chem. Phys. 147, 234308 (2017) be compared with those from recent studies of other L··· AgI a coupled-cluster method that includes single and double to allow trends to be established across a wide range of excitations, explicit correlation,28 and a perturbative treatment L··· AgI for the first time. of triple excitations.29 Basis set combinations consisting of aug-cc-pVXZ (X = T, Q) on C, H, and N and aug-cc-pVXZ-PP (X = T, Q) on Ag and I with relativistic effective core poten- II. METHODS tials MDF-2830,31 were used and will be referred to as AVXZ A. Experimental (X = T, Q). For the density fitting approximation which was used to accelerate the CCSD(T)(F12*) calculation, the respec- Broadband microwave spectra were measured using tive def2-QZVPP basis sets were employed for the MP2 and a chirped-pulse Fourier-transform microwave (CP-FTMW) Fock32 terms. For the complementary auxiliary basis required spectrometer fitted with a laser ablation source. Detailed for the F12 treatment,33 the def2-TZVPP MP2 density fitting descriptions of the spectrometer and laser ablation source are basis sets32 were used. Only valence electrons were included provided in Refs.9 and 23. The method employed to generate in the correlation treatment. H3N··· AgI is identical to that used previously during a study 3,5 of H2S··· AgI. A gas sample containing a low concentration of precursors is diluted in argon and prepared at a total pressure of 6 bars.