Infrared spectroscopy of the Li+(H2O)Ar complex: the role of internal energy and its dependence on ion preparation

Vaden, Timothy D.; Lisy, James M.; Carnegie, P. D.; Pillai, E. D.; Duncan, M. A.

doi:10.1039/b605442k

Cited by 67 publications

(107 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The spectroscopic work complements recent infrared investigations of clusters composed of simple metal cations such as Li + , Na + , K + , Mg + , Ca + , and Al + "solvated" by small molecules such as H 2 O, NH 3 , and CO 2 . Experimentally, perhaps the most direct way of probing these interactions is by spectroscopically studying complexes consisting of a single molecule attached to a metal cation, ideally in the gas phase.…”

Section: Introductionsupporting

confidence: 54%

The Al+–H2 cation complex: Rotationally resolved infrared spectrum, potential energy surface, and rovibrational calculations

Emmeluth

Poad

Thompson

et al. 2007

The Journal of Chemical Physics

View full text Add to dashboard Cite

The infrared spectrum of the Al(+)-H(2) complex is recorded in the H-H stretch region (4075-4110 cm(-1)) by monitoring Al(+) photofragments. The H-H stretch band is centered at 4095.2 cm(-1), a shift of -66.0 cm(-1) from the Q(1)(0) transition of the free H(2) molecule. Altogether, 47 rovibrational transitions belonging to the parallel K(a)=0-0 and 1-1 subbands were identified and fitted using a Watson A-reduced Hamiltonian, yielding effective spectroscopic constants. The results suggest that Al(+)-H(2) has a T-shaped equilibrium configuration with the Al(+) ion attached to a slightly perturbed H(2) molecule, but that large-amplitude intermolecular vibrational motions significantly influence the rotational constants derived from an asymmetric rotor analysis. The vibrationally averaged intermolecular separation in the ground vibrational state is estimated as 3.03 A, decreasing by 0.03 A when the H(2) subunit is vibrationally excited. A three-dimensional potential energy surface for Al(+)-H(2) is calculated ab initio using the coupled cluster CCSD(T) method and employed for variational calculations of the rovibrational energy levels and wave functions. Effective dissociation energies for Al(+)-H(2)(para) and Al(+)-H(2)(ortho) are predicted, respectively, to be 469.4 and 506.4 cm(-1), in good agreement with previous measurements. The calculations reproduce the experimental H-H stretch frequency to within 3.75 cm(-1), and the calculated B and C rotational constants to within approximately 2%. Agreement between experiment and theory supports both the accuracy of the ab initio potential energy surface and the interpretation of the measured spectrum.

show abstract

Section: Introductionsupporting

confidence: 54%

The Al+–H2 cation complex: Rotationally resolved infrared spectrum, potential energy surface, and rovibrational calculations

Emmeluth

Poad

Thompson

et al. 2007

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…This can be explained by considering that, due to its higher charge density, Li + is more effective in drawing electrons from the water molecule which, in turns, weakens the OH bonds and thus shifts the bending and (symmetric and asymmetric) stretching frequencies more to the blue and the red, respectively, compared to the other M + ions. In all cases, the LM vibrational frequencies are in good agreement with the available experimental values, [80][81][82] with deviation ranging from 20 to 30 cm −1 , depending on the ion. These differences may be due to a combination of different factors.…”

Section: Resultssupporting

confidence: 73%

Isomeric Equilibria, Nuclear Quantum Effects, and Vibrational Spectra of M+(H2O)n=1−3 Clusters, with M = Li, Na, K, Rb, and Cs, Through Many-Body Representations

Riera¹,

Brown²,

Paesani³

2018

Preprint

View full text Add to dashboard Cite

A quantitative characterization of the molecular mechanisms that regulate ion solvation is key to the microscopic understanding of fundamental processes taking place in aqueous environments, with major implications for different fields, from atmospheric chemistry to materials research and biochemistry. This study presents a systematic analysis of isomeric equilibria for small M + (H 2 O) n clusters, with M = Li, Na, K, Rb, and Cs, from 0 K to 200 K. To determine the relative stability of different isomers of 1 each M + (H 2 O) n cluster as a function of temperature, replica exchange simulations are carried out at both classical and quantum levels with the recently developed many-body MB-nrg potential energy functions, which have been shown to exhibit chemical accuracy. Anharmonic vibrational spectra are then calculated within the local monomer approximation and found to be in agreement with the available experimental data, providing further support for the accuracy of the MB-nrg potential energy functions.The present analysis indicates that nuclear quantum effects become increasingly important for larger M + (H 2 O) n clusters containing the heavier alkali metal ions, which is explained in terms of competing ion-water and water-water interactions along with the interplay between energetic and entropic effects. Directly connecting experimental measurements with molecular properties calculated at the quantum mechanical level, this study represents a further step toward the development of a consistent picture of ion hydration from the gas to the condensed phase.

show abstract

“…·Ar (3629 and 3691 cm À1 ), [46] and Ni 2 (3623 and 3696 cm À1 ). [13] Duncan and co-workers have explained this red shift through partial electron transfer from the water molecule to the charge, [13] causing a frequency shift analogous to the extremely red-shifted u sym and u asym modes observed for H 2 O + C at 3213 and 3259 cm…”

mentioning

confidence: 99%

Hydration of the Calcium Dication: Direct Evidence for Second Shell Formation from Infrared Spectroscopy

2007

View full text Add to dashboard Cite

Infrared laser action spectroscopy in a Fourier-transform ion cyclotron resonance mass spectrometer is used in conjunction with ab initio calculations to investigate doubly charged, hydrated clusters of calcium formed by electrospray ionization. Six water molecules coordinate directly to the calcium dication, whereas the seventh water molecule is incorporated into a second solvation shell. Spectral features indicate the presence of multiple structures of Ca(H2O)(7)2+ in which outer-shell water molecules accept either one (single acceptor) or two (double acceptor) hydrogen bonds from inner-shell water molecules. Double-acceptor water molecules are predominantly observed in the second solvent shells of clusters containing eight or nine water molecules. Increased hydration results in spectroscopic signatures consistent with additional second-shell water molecules, particularly the appearance of inner-shell water molecules that donate two hydrogen bonds (double donor) to the second solvent shell. This is the first reported use of infrared spectroscopy to investigate shell structure of a hydrated multiply charged cation in the gas phase and illustrates the effectiveness of this method to probe the structures of hydrated ions.

show abstract

Infrared spectroscopy of the Li+(H2O)Ar complex: the role of internal energy and its dependence on ion preparation

Cited by 67 publications

References 45 publications

The Al+–H2 cation complex: Rotationally resolved infrared spectrum, potential energy surface, and rovibrational calculations

The Al+–H2 cation complex: Rotationally resolved infrared spectrum, potential energy surface, and rovibrational calculations

Isomeric Equilibria, Nuclear Quantum Effects, and Vibrational Spectra of M+(H2O)n=1−3 Clusters, with M = Li, Na, K, Rb, and Cs, Through Many-Body Representations

Hydration of the Calcium Dication: Direct Evidence for Second Shell Formation from Infrared Spectroscopy

Contact Info

Product

Resources

About