HF Clusters Research Articles

STRUCTURES, ELECTRONIC, AND MAGNETIC PROPERTIES OF TRANSITION METAL-INSERTED H2DBP CLUSTERS

The configurations, electronic, and magnetic properties of the H2DBP-M clusters have been investigated via density functional theory. The results reveal that the TM atoms for the H2DBP-M ([Formula: see text], Y, Zr, Nb, Lu, and Hf) clusters deviate from the center planes of the clusters. The H2DBP-M ([Formula: see text], Y, and Lu) clusters display the largest dipole magnitudes. Based on the binding energy per atom and HOMO-LUMO gap, the H2DBP-Ni and H2DBP-Lu clusters are the most favorable for synthesis. The charge transfer amounts of the TM ([Formula: see text], Zn, Y, Cd, Hf, and Hg) atoms for the H2DBP-M clusters are larger. The TM-d orbitals of the H2DBP-M ([Formula: see text]Co and Cu) clusters contribute significantly to the Fermi levels. The spin densities of the TM atoms for the H2DBP-M clusters reduce to 0 except for that ([Formula: see text]) of the H2DBP-V clusters.

Identification of Histone Acetylation Regulator KAT2A As a Potential Prognostic Biomarker in Diffuse Large B-Cell Lymphoma

Introduction Diffuse large B-cell lymphoma (DLBCL) is a highly heterogeneous lymphoid neoplasm with variations in the expression of genes and genetic alterations. Epigenetic alterations are associated with lymphoma pathogenesis, one of which is histone acetylation. Ferroptosis is a novel type of cell death with distinct properties and recognizing functions involved in physical conditions or various cancers. However, the functions of histone acetylation and ferroptosis in DLBCL remain unclear. Our study assesses the significance and mechanisms of ferroptosis-related genes (FRG) and histone acetylation regulators (HAG). Methods Using consensus clustering, we categorized DLBCL patients based on histone acetylation regulators and ferroptosis-related genes (HFGs) expression. The WGCNA identified genes and mechanisms that affect HF clusters. LASSO Cox regression was used to calculate risk scores. To assess the accuracy of this model, Kaplan-Meier survival analysis, univariate and multivariate Cox regression analysis, and ROC curve analysis were performed. qRT-PCR was used to validate the expression of four HFGs in DLBCL cell lines. Results A total of 38 HA regulators were evaluated for mutations. According to the study, CREBBP had the highest mutation frequency. Based on CREBBP mutations, patients were divided into mutant and wild groups, and several histone acetylation regulators were overexpressed in the mutant group. There was a high rate of copy number variation (CNV) in some genes. To demonstrate the potential malignant mechanisms of HFGs in DLBCL development and their prognostic value. A significant positive self-correlation was observed in HAGs and FRGs. A negative correlation was found between KAT2A, the HA writer, and the majority of FRGs (Fig. 1A). 36 genes were selected (P < 0.05) by univariate regression correlations with clinical prognosis. Consensus clustering was used to categorize the expression of DLBCL patients. K-M survival analysis showed that HFcluster B had a worse prognosis. To investigate the underlying mechanisms, WGCNA was used to divide genes into different modules. Afterwards, we selected the blue and green modules to analyze their functions. KEGG enrichment emphasized oncological pathways like PI3K-Akt, focal adhesion, Hippo, and MAPK signaling pathway. Based on HFGs and their corresponding signatures, we developed a high-quality and high-accuracy gene signature prediction model. Following LASSO Cox regression, a four-gene signature model was identified. Patients with DLBCL in the high-risk group had a significantly shorter OS (P < 0.001, Fig. 1B). ROC curves, univariate and multivariate Cox regression analyses also revealed that riskScore served as an independent indicator for patients with DLBCL (P < 0.001). GSEA enrichment analysis identified JAK-STAT, P53, and APOPTOSIS as the most differentially enriched genes for malignant mechanisms. Analyses revealed that molecular mechanisms mediate histone acetylation and ferroptosis. The results of PCR in CD19+ B cells and DLBCL cell lines also confirmed the accuracy of the model. Due to its close relationship to ferroptosis-related genes, KAT2A was explored in greater depth. Further study revealed that KAT2A was significantly correlated with age (P = 0.028) and IPI (P = 0.016). In univariate analysis, KAT2A was an independent indicator of DLBCL patients (P < 0.001). The expression level of KAT2A was negatively correlated with OS in DLBCL patients (P = 0.003). Conclusions There were significant correlations among these HFGs, indicating their potential role in DLBCL development and predictive value for prognosis. Additionally, our study shows that KAT2A is associated with prognosis in patients with DLBCL. Further study of the mechanisms of KAT2A in DLBCL may help clinicians to individualize the treatment of this patient population. Keywords: histone acetylation, ferroptosis, mechanism, DLBCL Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Full-route advances via biomimetic and biodegradable ultrasmall-in-nano architectures with radiation-photo synergy

The overall therapeutic output is significantly affected by the route of nanomedicines in vivo, including the successive steps of delivery, exogenous excitation, and final metabolism, thus requiring the elaborate composition and structure of nanomedicines. To develop nanomedicines with the full-route advances, we have designed and architected the biomimetic and biodegradable ultrasmall-in-nano particles (UiNP, 80 nm) with the radiation-photo synergy for the first time, by utilizing cancer cell membrane (CCM) nanovehicles to camouflage multiple ultrasmall particles (UP6, 6 nm) composed of Chlorin e6 (Ce6) and hafnium (Hf) clusters via the covalent coordination. The UiNP with the camouflage effect, homotypic adhesion and suitable size can obtain 4-fold blood circulation half-live that of UP6 and 2.5-fold accumulation level that of nanoparticle (NP180, 180 nm), achieving delivery advance. Moreover, the UiNP not only exhibit a dual-modal X-ray therapy with radio-radiodynamic effect via energy transfer but also afford a dual-modal phototherapy with photodynamic-photothermal effect by adjusting the radiative-nonradiative transition of Ce6 within the confined space, thus balancing the killing efficacy and the penetration depth for therapeutic advance. Furthermore, benefiting from the ultrasmall size and intrinsic biodegradability of UP6 and CCM camouflage, the UiNP are less accumulated in reticuloendothelial organs than NP180 and thereby rapid metabolize via urine and feces, exerting the metabolic advance. Therefore, such novel UiNP architectures with full-route advances are much superior to the conventional agents, which can provide some insights for developing new types of ultrasmall-in-nano agents.

The forgotten chemistry of group(IV) metals: A survey on the synthesis, structure, and properties of discrete Zr(IV), Hf(IV), and Ti(IV) oxo clusters

• Group IV metal oxo clusters (MOCs) applications in materials and catalysis are rapidly expanding. • Group IV MOCs are prepared in aqueous or organic medium with a variety of ligands. • Ligands influence structure and properties, thus impacting materials syntheses and catalysis. • Ligand-exchanged happens with or without rearrangement of the inorganic core. Group (IV) metal oxo clusters are a diverse class of compounds with rapidly growing applications in catalysis, materials chemistry, electronics and optics. They possess unique structural stability, reactivity and electronic properties; however, their potential remains underexplored due to the gaps in fundamental understanding about their structure, intrinsic features, and nuances in their synthesis that overall would allow for great tunability of their properties. In this context, here we review the chemistry of discrete zirconium, hafnium, and titanium metal oxo clusters reported in the literature in order to provide a critical overview of the structural features, properties and reactivity disclosed to date. While a comprehensive summary of Zr and Hf clusters is presented, only the most recent Ti oxo clusters are discussed in addition to some key compounds that have been revised elsewhere. Envisioning the growing relevance group (IV) metal oxo clusters for the synthesis of nanostructure materials and in catalysis, we also summarize key principles of their surface chemistry, and the photoactivity of Ti oxo clusters, given the paramount importance of these properties for the development of future applications.

Oxidation of amorphous HfNbTaTiZr high entropy alloy thin films prepared by DC magnetron sputtering

High entropy alloys represent a new type of materials with a unique combination of physical properties originating from the occurrence of single-phase solid solutions of numerous elements. The preparation of nanostructured or amorphous structure in a form of thin films promises increased effective surface and high intergranular diffusion of elements as well as a high affinity to oxidation. In this work, we studied HfNbTaTiZr thin films, deposited at room temperature by DC magnetron sputtering from a single bcc phase target. Films exhibit cellular structure (∼100 nm) with fine substructure (∼10 nm) made of round-shape amorphous clusters. The composition is close to equimolar with slight Ti enrichment and without any mutual segregation of elements. Oxidation at the ambient atmosphere leads to the formation of Ti, Zr, Nb, Hf, and Ta oxide clusters in the film up to the depth of 200–350 nm out of the total film thickness of 1650 nm. Oxygen absorption takes place preferentially in the large vacancy clusters located in between the amorphous cluster aggregates. The dominant type of defect are small open volumes with a size comparable with vacancy. The distribution of these defects is uniform with depth and is not influenced by the presence of oxygen in the film.

Ab initio investigations on non-metallic chain-shaped FnHn+1+ series of superalkali cations

FnHn+1+ cations (n = 1–10) have been systematically explored using ab initio MP2/6-311++G(d,p) and molecular dynamics methods. These cations possess chain-like geometrical structures comprised of the FH2 or F2H3 cores in dependence on the n parity. Ab initio molecular dynamics, as well as deprotonation and HF-reduction energies, suggest the stability of these cations. FnHn+1+ cations exhibit superalkali nature for n > 1, as their vertical electron affinity decays exponentially from 4.48 eV to 1.60 eV as n increases from 2 to 10. This study offers new insights into the protonated HF clusters and demands further explorations in this direction.

2-body:Many-body QM:QM study of structures, energetics, and vibrational frequencies for microhydrated halide ions

ABSTRACTThe optimised structures, electronic dissociation energies and harmonic vibrational frequencies of microhydrated halide ions have been probed with the MP2 and CCSD(T) quantum mechanical (QM) electronic structure techniques as well as with the 2-body:Many-body QM:QM method (2b:Mb CCSD(T):MP2) in which the 1- and 2-body interactions are computed at the CCSD(T) level of theory while all higher-order contributions are captured at the MP2 level of theory. In general, the accuracy and efficiency of the 2b:Mb approach previously demonstrated for neutral, homogeneous HF and HO clusters extends to these negatively charged heterogeneous systems. Results indicate the MP2 method struggles to provide a reliable description of the vibrational frequencies for hydrated fluoride clusters even though it performs well for the other hydrated halides (chloride, bromide and iodide). Consequently, the accuracy of the 2b:Mb CCSD(T):MP2 approach for fluoride clusters is poorer than the other halides, and MP2 is not a recommended low-level method for high-accuracy frequency analyses of hydrated fluoride complexes with the 2b:Mb method or related QM:QM approaches.

Formation and structural growth of two dimensional layer of hafnene on Ir(1 1 1) surface

We have investigated the structures and stability of two dimensional (2D) Hf clusters on Ir(1 1 1) surface as the initial stage of hafnene growth using first principles density functional theory (DFT) with the generalized gradient approximation. The study reveals that the Ir supported Hf clusters of n hexagonal rings prefer a nearly flat honeycomb structure, with the exception of n = 1. The 2D Hf clusters, unlike to that of free-standing hafnene monolayer, exhibits no magnetic property mainly due to strong hybridization with the Ir(1 1 1) surface. A thorough investigation has also identifies the most stable structures and corresponding physical properties of free standing HfN(N≤24) clusters.

Effect of laser conditioning on nanoprecursor for improving laser damage resistance of HfO2 coatings

An experimental and analytical approach is described to investigate the effect of laser conditioning on the nanoprecursor of the Hf cluster for improving the damage resistance of HfO2 coatings. Two test methods of 1-on-1 and R-on-1 (usually, R-on-1 is referred to as laser conditioning) were employed to measure the damage probabilities of samples of HfO2 coating. In addition, the measured damage probabilities of 1-on-1 and R-on-1 were compared with the simulations based on Mie scatter theory, heat transfer and damage probability calculation to determine the size distribution of the nanoprecursor of the Hf cluster, which indicates the decrease in their sizes. X-ray photoelectron spectroscopy analysis reveals that laser conditioning has increased the relative oxygen content, which implies that a portion of Hf atoms in the nanoprecursors are oxidized to HfO2 due to O atoms from the decomposed water and air, with a resulting decrease in their size and absorption and an increase in their laser damage threshold. The experimental and simulative results indicate that the size decrease and distribution variation of the Hf clusters may be another one of the mechanisms for laser conditioning to increase the damage resistance of HfO2 coatings.

Direct Synthesis of Hierarchically Porous Metal–Organic Frameworks with High Stability and Strong Brønsted Acidity: The Decisive Role of Hafnium in Efficient and Selective Fructose Dehydration

The direct synthesis of metal–organic frameworks (MOFs) with strong Brønsted acidity is challenging because the functional groups exhibiting Brønsted acidity (e.g., sulfonic acid groups) often jeopardize the framework integrity. Herein, we report the direct synthesis of two hierarchically porous MOFs named NUS-6 composed of either zirconium (Zr) or hafnium (Hf) clusters with high stability and strong Brønsted acidity. Via the modulated hydrothermal (MHT) synthesis, these two MOFs can be easily synthesized at a low temperature (80 °C) with high throughput. They exhibit BET surface areas of 550 and 530 m2 g–1 for Zr and Hf one, respectively, and a unique hierarchically porous structure of coexisting micropores (∼0.5, ∼0.7, and ∼1.4 nm) and mesopores (∼4.0 nm) with dangling sulfonic acid groups. Structural analysis reveals that the hierarchical porosity of NUS-6 is a result of missing linkers and clusters of the parental UiO-66 framework. These unique features make NUS-6 highly efficient and selective solid acid catalysts for dehydration of fructose to 5-hydroxymethylfurfural (HMF), in which NUS-6(Hf) demonstrates a superior performance versus that of NUS-6(Zr) because of the stronger Brønsted acidity contributed from Hf-μ3-OH groups as well as smaller pore sizes suitable for the restriction of unwanted side reactions. Our results have demonstrated for the first time the unique attributes of Hf-MOFs featured by superior stability and Brønsted acidity that can be applied as heterogeneous catalysts in biobased chemical synthesis.

Improvement of aging kinetics and precipitate size refinement in Mg–Sn alloys by hafnium additions

Two Mg–Sn alloys were microalloyed by addition of Hafnium and their age-hardening response was studied at 200°C. Time to reach peak hardness was significantly reduced and improved by Hf addition. TEM study showed Hf clusters in the close vicinity and at the surface of Mg2Sn precipitates, which confirms that Hf clusters act as additional nucleation centers for Mg2Sn precipitate formation. Our results support the validity of thermokinetic criterion proposed by Mendis for selection of microalloying elements in order to refine precipitate size, accelerate aging kinetics and enhance peak hardness.

Hafnium Sulfate Prenucleation Clusters and the Hf18 Polyoxometalate Red Herring

In prior studies, aqueous Hf sulfate-peroxide solutions were spin-coated, dehydrated, patterned by electron-beam lithography, ion-exchanged (OH(-) for SO4(2-)), and finally converted to HfO2 hard masks via annealing. The atomic-level details of the underlying aqueous chemistries of these processes are complex and yet to be understood. Yet a thorough understanding of this specific chemical system will inspire development of design rules for other aqueous-precursor-to-solid-state metal oxide systems. Often-observed crystallization of the Hf18 polyoxometalate from aqueous Hf sulfate-peroxide precursor solutions has led us to believe that Hf18 may represent an important intermediate step in this process. However, via detailed solution studies described here (small-angle X-ray scattering, electrospray ionization mass spectrometry, and Raman spectroscopy), we ascertained that Hf18 is in fact not a prenucleation cluster of Hf sulfate coatings. Rather, the Hf tetramers, pentamers, and hexamers that are the core building blocks of Hf18 are robustly persistent over variable compositions and aging time of precursor solutions, and therefore they are likely the rudimentary building blocks of the deposited thin-film materials. These Hf clusters are capped and linked by sulfate and peroxide anions in solution, which probably prevents crystallization of Hf18 during the rapid dehydration process of spin-coating. In fact, crystallization of Hf18 from the amorphous gel coating would be detrimental to formation of a high-density conformal coating that we obtain from precursor solutions. Therefore, this study revealed that the well-known Hf18 polyoxometalate is not likely to be an important intermediate in the thin-film process. However, its subunits are, confirming the universal importance of deriving information from the solid state, albeit judiciously and critically, to understand the solution state.

Optical Properties and Quasiparticle Band Gaps of Transition-Metal Atoms Encapsulated by Silicon Cages

Semiconductors assembled upon nanotemplates consisting of metal-encapsulating Si cage clusters (M@Sin) have been proposed as prospective materials for nanodevices. To make an accurate and systematic prediction of the optical properties of such M@Sin clusters, which represent a new type of metal–silicon hybrid material for components in nanoelectronics, we have performed first-principles calculations of the electronic properties and quasiparticle band gaps for a variety of M@Si12 (M = Ti, Cr, Zr, Mo, Ru, Pd, Hf, and Os) and M@Si16 (M = Ti, Zr, and Hf) clusters. At first stage, the electronic structure calculations have been performed within plane-wave density functional theory in order to predict equilibrium geometries, polarizabilities, and optical absorption spectra of these endohedral cagelike clusters. The quasiparticle calculations were performed within the GW approximation, which predict that all of these systems are semiconductors exhibiting large band gaps. The present results have demonstrated that the independent-particle absorption spectra of M@Sin, calculated within the local density or generalized gradient approximations to density functional theory, are dramatically influenced by many-body effects. On average, the quasiparticle band gaps were significantly increased, in comparison with the independent-particle gaps, giving values in the 2.45–5.64 eV range. Consequently, the inclusion of many-body effects in the electron–electron interaction, and going beyond the mean-field approximation of independent particles, might be essential to realistically describe the optical spectra of isolated M@Sin clusters, as well as their cluster-assembled materials.

Spectroscopy of HF and HF-Containing Clusters in Solid Parahydrogen

We report measurements of FT-IR absorption spectroscopy of HF, DF, and their clusters in solid parahydrogen (pH(2)). The observed spectra contain many absorption lines which were assigned to HF monomers, HF polymers, and clusters with other species, such as N(2), O(2), orthohydrogen (oH(2)), etc. The rotational constants of HF and DF monomers were determined from the cooperative transitions of the vibration of solid pH(2) and the rotation of HF and DF. Small reduction of the rotational constants indicates that HF and DF are nearly free rotors in solid pH(2). Time dependence of the spectra suggests that HF and DF monomers migrate in solid pH(2) and form larger polymers, probably via tunneling reactions through high energy barriers on inserting another monomer to the polymers. The line width of HF monomers in solid pH(2) was found to be 4 cm(-1), which is larger than that of other hydrogen halides in solid pH(2). This broad line width is explained by rapid rotational relaxation due to the accidental coincidence between the rotational energy of HF and the phonon energy with maximum density of states of solid pH(2) and the rotational-translational coupling in a trapping site.

ChemInform Abstract: Gold Behaves as Hydrogen in the Intermolecular Self‐Interaction of Metal Aurides MAu4 (M: Ti, Zr, and Hf)

AbstractDFT calculations

Gold Behaves as Hydrogen in the Intermolecular Self‐Interaction of Metal Aurides MAu4 (M=Ti, Zr, and Hf)

We performed density functional calculations to examine the intermolecular self-interaction of metal tetraauride MAu(4) (M = Ti, Zr, and Hf) clusters. We found that the metal auride clusters have strong dimeric interactions (2.8-3.1 eV) and are similar to the metal hydride analogues with respect to structure and bonding nature. Similarly to (MH(4))(2), the (μ-Au)(3) C(s) structures with three three-center two-electron (3c-2e) bonds were found to be the most stable. Natural orbital analysis showed that greater than 96 % of the Au 6s orbital contributes to the 3c-2e bonds, and this predominant s orbital is responsible for the similarity between metal aurides and metal hydrides (>99 % H 1s). The favorable orbital interaction between occupied Au 6s and unoccupied metal d orbitals leads to a stronger dimeric interaction for MAu(4)-MAu(4) than the interaction for MH(4)-MH(4). There is a strong relationship between the dimeric interaction energy and the chemical hardness of its monomer for (MAu(4))(2) and (MH(4))(2).

The role of electron localization in the atomic structure of transition-metal 13-atom clusters: the example of Co13, Rh13, and Hf13

The crystalline structure of transition-metals (TM) has been widely known for several decades, however, our knowledge on the atomic structure of TM clusters is still far from satisfactory, which compromises an atomistic understanding of the reactivity of TM clusters. For example, almost all density functional theory (DFT) calculations for TM clusters have been based on local (local density approximation--LDA) and semilocal (generalized gradient approximation--GGA) exchange-correlation functionals, however, it is well known that plain DFT fails to correct the self-interaction error, which affects the properties of several systems. To improve our basic understanding of the atomic and electronic properties of TM clusters, we report a DFT study within two nonlocal functionals, namely, the hybrid HSE (Heyd, Scuseria, and Ernzerhof) and GGA+U functionals, of the structural and electronic properties of the Co(13), Rh(13), and Hf(13) clusters. For Co(13) and Rh(13), we found that improved exchange-correlation functionals decrease the stability of open structures such as the hexagonal bilayer (HBL) and double simple-cubic (DSC) compared with the compact icosahedron (ICO) structure, however, DFT-GGA, DFT-GGA+U, and DFT-HSE yield very similar results for Hf(13). Thus, our results suggest that the DSC structure obtained by several plain DFT calculations for Rh(13) can be improved by the use of improved functionals. Using the sd hybridization analysis, we found that a strong hybridization favors compact structures, and hence, a correct description of the sd hybridization is crucial for the relative energy stability. For example, the sd hybridization decreases for HBL and DSC and increases for ICO in the case of Co(13) and Rh(13), while for Hf(13), the sd hybridization decreases for all configurations, and hence, it does not affect the relative stability among open and compact configurations.

ChemInform Abstract: New Ternary Hafnium Tellurides Hf8Te6M (M: Mn, Fe) Containing M- Centered Tetrakaidecahedra.

The synthesis of the new ternary hafnium tellurides Hf[sub 8]Te[sub 6]M (M = Mn, Fe) is reported. The single-crystal structure of the Mn-containing compound has been determined. Hf[sub 8]Te[sub 6]Mn crystallizes in the orthorhombic space group Pmmn (No. 59) with lattice parameters a = 25.816 [angstrom], b = 3.7614 [angstrom], c = 7.605 [angstrom] (Z = 2); the lattice parameters for the Fe analog show a slight shortening of the b axis: a = 25.815 [angstrom], b = 3.7309 [angstrom], c = 7.598 [angstrom]. The Hf[sub 8]Te[sub 6]M structure possesses tricapped trigonal-prismatic Hf clusters centered by M. The trigonal prism dimensions are such that Hf-Hf contacts between triangular faces are long (3.761 [angstrom]) and the triangular faces themselves are isosceles (d(Hf-Hf): 2 [times] 3.160 [angstrom], 3.565 [angstrom]). The Te atoms are 4-, 5-, and 6-coordinate with respect to Hf and serve to sheath the metal framework to produce large Te-lined cavities within the structure. Resistivity measurements between 77 and 250 K show Hf[sub 8]Te[sub 6]Mn to be metallic as predicted by band-structure calculations. The same calculations also indicate that Hf-M bonding is of overriding importance in stabilizing these metal-metal bonded structures. There is no significant Te-Te bonding. 44 refs., 8more » figs., 5 tabs.« less

Phase formation and structures of quasicrystals and approximants in the Zn–Mg–(Ti, Zr, Hf) system

The compositional regions for primitive (P) and face-centered (F) icosahedral quasicrystals (iQc) have been determined to be around Zn 84Mg 9Zr 7 and Zn 75Mg 18Zr 6, respectively. A 1/1 approximant of the F-type iQc was found to have a composition around Zn 77Mg 18Zr 5. A similar tendency has been verified for the Zn–Mg–Hf system. No stable iQc was observed in the Zn–Mg–Ti system. High-resolution X-ray measurements performed with synchrotron radiation showed that the stable iQcs are highly ordered and contain less phason disorder. High-angle annular dark field (HAADF) scanning transmission electron microscopy observation of the 1/1 Zn–Mg–Hf approximant effectively revealed the Hf positions in the structure, whose local contrasts can be reasonably interpreted by a structural model where icosahedral and dodecahedral Hf clusters are mutually interpenetrated. Similar appearances of local contrasts were frequently observed in HAADF images of the F-type iQc, indicating that the iQc structure is also build up of icosahedral clusters that are almost identical to those in the 1/1 approximant.

Hydration and Dissociation of Hydrogen Fluoric Acid (HF)

The hydration and dissociation phenomena of HF(H(2)O)(n)() (n < or = 10) clusters have been studied by using both the density functional theory with the 6-311++G[sp] basis set and the Møller-Plesset second-order perturbation theory with the aug-cc-pVDZ+(2s2p/2s) basis set. The structures for n > or = 8 are first reported here. The dissociated form of the hydrogen-fluoric acid in HF(H(2)O)(n) clusters is found to be less stable at 0 K than the undissociated form until n = 10. HF may not be dissociated at 0 K solely by water molecules because the HF H bond is stronger than the OH H bond, against the expectation that the dissociated HF(H(2)O)(n) would be more stable than the undissociated one in the presence of a number of water molecules. The dissociation would be possible for only a fraction of a number of hydrated HF clusters by the Boltzmann distribution at finite temperatures. This is in sharp contrast to other hydrogen halide acids (HCl, HBr, HI) showing the dissociation phenomena at 0 K for n > or = 4. The IR spectra of dissociated and undissociated structures of HF(H(2)O)(n) are compared. The structures and binding energies of HF(H(2)O)(n) are found to be similar to those of (H(2)O)(n+1). It is interesting that HF(H(2)O)(n=5,6,10) are slightly less stable compared with other sizes of clusters, just like the fact that (H(2)O)(n=6,7,11) are slightly less stable. The present study would be useful for the experimental/spectroscopic investigation of not only the dissociation phenomena of HF but also the similarity of the HF-water clusters to the water clusters.