Binding energy, structure, and vibrational spectra of (HCl)2–6 and (HF)2–10 clusters by density functional theory

Abstract

We are reporting density functional theory results for the binding energies, structures, and vibrational spectra of (H-Cl) 2-6 and (H-F) 2-10 clusters. The performance of different functionals has been investigated. The properties of HF clusters predicted by hybrid functionals are in good agreement with experimental information. The HCl dimer binding energy ⌬E e is underestimated by hybrid functionals. The Perdew and Wang exchange and correlation functional ͑PW91͒ result for ⌬E e is Ϫ9.6 kJ mol Ϫ1 , in very good agreement with experiment (Ϫ9.5 kJ mol Ϫ1). However, PW91 overestimates binding energies of larger clusters. Hydrogen bonding cooperativity depends on the cluster size n but reaches a limit for moderately sized clusters (nϭ8 for HF). The average shift to low frequencies ͑⌬͒ of the X-H (XϭCl,F) stretching vibration relative to the monomer is in good agreement with experimental data for HF clusters in solid neon. However, some discrepancies with experimental results for HCl clusters were observed. The behavior of ⌬ as a function of the cluster size provides an interesting illustration of hydrogen-bond cooperative effects on the vibrational spectrum. The representation of the electronic density difference shows the rearrangement of the electronic density induced by hydrogen bonding in the clusters and supports the view that hydrogen-bond cooperativity is related to electronic sharing and delocalization.

Fluorines in tetrafluoromethane as halogen bond donors: Revisiting address the nature of the fluorine'sσhole

“…Δ E sm for the (YD) n ···F 4 C clusters are also negative, meaning that weak nonadditive cooperative effects are sharply evident which enhance the overall cluster stabilities, arising from the mutual polarization of the interacting partners. Note that the Δ E sm values decrease monotonically when one moves from binary to tertiary, and from tertiary to quaternary, and from tertiary to quinary clusters; the feature is somehow analogous to the results of Guedes et al for the (HCl) n and (HF) n clusters . The decrease noted just above in particular is more prominent for the clusters of CF 4 with HCN, for which, the Δ E s3 and Δ E s4 values are more positive for (HCN) 3 ···F 4 C and (HCN) 4 ···F 4 C (+0.07 vs. +1.47 kJ mol −1 ), reflecting the emergence of an anticooperative effect on the formation of these latter two clusters.…”

Stereographic projection path integral simulations of (HCl)n clusters (n=2–5): Evidence of quantum induced melting in small hydrogen bonded networks

“…Its structure is very similar to what is reported in the literature. 16 We measure the torsion angle associated with the four chlorine atoms in the four member ring. Its value is 38.89°, smaller than the torsion measured for M 4.1 , 47.3°.…”

“…The experimental efforts have been paralleled by a number of theoretical investigations. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] For HCl clusters, in particular, a highly accurate potential energy surface ͑PES͒ has been refined by several investigators. [17][18][19][20][21][22] Its latest version 17 is a third generation model capable of reproducing high resolution spectroscopy data, and making accurate predictions to guide future experiments.…”

“…15 Beyond the HCl dimer, however, there are only few theoretical investigations. 16,21 While the bulk of the experimental effort relies on the relatively weak coupling between the covalent stretching and the intermolecular degrees of freedom, the thermodynamics of HF and HCl clusters is dominated by the strong coupling between translation and rotation DFs. The combination of the strong anisotropic nature of the hydrogen bond and the large coupling among very different intermolecular DF is likely to produce unusual and unique thermodynamic properties.…”

Collision-induced dissociation products of the protonated dipeptide carnosine: structural elucidation, fragmentation pathways and potential energy surface analysis

“…However, studies employing DFT calculations with the B3LYP functional accurately detail hydrogen bonding in small systems such as hydrogen fluoride dimers, clusters of cyanoacetylene and hydrogen cyanide as well as in water dimers and complexes. [51][52][53][54] The B3LYP and 6-31++G(d,p) combination was successfully used to model internal hydrogen bonding within a protonated triglycine and to demonstrate the validity of the ''mobile proton'' model in the tripeptide, 55 while the B3LYP/6-311++G(2d,2p) level of theory was shown to predict the existence of a hydrogen bonding stabilised zwitterionic form of protonated carnosine in the gas phase. 21 With the aim of comparing, however, both single point MP2 (frozen core) 56 and M06 57 calculations were carried out by using the same 6-311++G(d,p) basis set on optimized B3LYP/6-311++G(d,p) geometries.…”