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Jan Makarewicz - One of the best experts on this subject based on the ideXlab platform.
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ab initio intermolecular potential energy surfaces of the water rare Gas Atom complexes
Journal of Chemical Physics, 2008Co-Authors: Jan MakarewiczAbstract:Highly accurate analytical intermolecular potential energy surfaces (PESs) of the complexes composed of the water molecule and the rare Gas (Rg) Atom are presented for Rg=He, Ne, Ar, and Kr. These PESs were scanned using the supermolecule coupled cluster singles and doubles including connected triples method [CCSD(T)]. Efficient basis sets including the bond functions (3s3p2d1f1g) enabled the calculation of more than 430 single-point interaction energies for each complex. These energies were utilized to construct the analytical many-body representations of the PESs. They were refined using the interaction energies evaluated at the complete basis set limit in the PES stationary points. In addition, the corrections from the core correlation were calculated for the complexes including He, Ne, and Ar. The many-body PES of XeH2O was built using the ab initio energy values reported by Wen and Jager [J. Phys. Chem. A 110, 7560 (2006)]. The clear regularities of the equilibrium structure and the potential barrier...
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the helium neon and argon cyclopropane van der waals complexes ab initio ground state intermolecular potential energy surfaces and intermolecular dynamics
Journal of Chemical Physics, 2001Co-Authors: Thomas Bondo Pedersen, Berta Fernandez, Henrik Koch, Jan MakarewiczAbstract:Using the coupled cluster singles and doubles including connected triples model and the augmented correlation consistent polarized valence double zeta basis set extended with a set of 3s3p2d1f1g midbond functions, ab initio helium–, neon–, and argon–cyclopropane ground state intermolecular potential energies are evaluated and fitted to an analytic function including up to four-body interactions. These are the first ab initio potential energy surfaces available for these complexes and are characterized by an absolute minimum of −73.3 cm−1 at a distance on the cyclopropane C3-axis of 3.291 A, −125.3 cm−1 at 3.435 A, and −301.1 cm−1 at 3.696 A for helium, neon, and argon, respectively. The bound van der Waals states are calculated. Two types of tunneling motion cause splittings of these levels: a C3 tunneling between the three equivalent local minima placed in the cyclopropane plane, and a C2 tunneling motion of the rare Gas Atom between the global minima above and below the cyclopropane plane.
Tapan K. Ghanty - One of the best experts on this subject based on the ideXlab platform.
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noble Gas inserted protonated silicon monoxide cations hngosi ng he ne ar kr and xe
Journal of Physical Chemistry A, 2015Co-Authors: Pooja Sekhar, Ayan Ghosh, Tapan K. GhantyAbstract:The existence of noble Gas containing protonated silicon monoxide complexes have been predicted theoretically through ab initio quantum chemical methods. The predicted HNgOSi+ ions are obtained by insertion of a noble Gas Atom (Ng = He, Ne, Ar, Kr, and Xe) between the H and O Atoms in SiOH+ ion. The structural parameters, energetics, harmonic vibrational frequencies, and charge distributions have been analyzed by optimizing the minima and the transition state structures using second-order Moller–Plesset perturbation theory (MP2), density functional theory (DFT), and coupled-cluster theory (CCSD(T)) based techniques. The predicted HNgOSi+ ions are found to be stable with respect to all possible 2-body and 3-body dissociation channels, except the dissociation path leading to the respective global minimum products. However, these ions are found to be kinetically stable with respect to the global minimum dissociation process as revealed from the finite barrier heights, which in turn can prevent the transforma...
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theoretical prediction of rare Gas inserted hydronium ions hrgoh2
Journal of Chemical Physics, 2013Co-Authors: Ayan Ghosh, Debashree Manna, Tapan K. GhantyAbstract:A possibility of existence of new species through insertion of a rare Gas Atom in hydronium ion resulting into HRgOH2+ cation (Rg = He, Ar, Kr, and Xe) has been explored by using various ab initio quantum chemical techniques. Structure, harmonic vibrational frequencies, stability, and charge distribution of HRgOH2+ species as obtained using density functional theory, second order Moller-Plesset perturbation theory, and coupled-cluster theory based methods are reported in this work. All the calculated results suggest that the HRgOH2+ species are stable enough with respect to all the dissociation channels, except the 2-body dissociation path (H3O+ + Rg). Nevertheless, this 2-body dissociation channel connected through the relevant transition state is associated with a finite barrier, which in turn would prevent the metastable species in transforming to global minimum products. The calculated values of topological properties within the framework of quantum theory of Atoms-in-molecules are found to be consist...
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how strong is the interaction between a noble Gas Atom and a noble metal Atom in the insertion compounds mngf m cu and ag and ng ar kr and xe
Journal of Chemical Physics, 2006Co-Authors: Tapan K. GhantyAbstract:Ab initio molecular orbital calculations have been carried out to investigate the structure and the stability of noble Gas insertion compounds of the type MNgF (M=Cu and Ag, and Ng=Ar, Kr, and Xe) through second order Moller-Plesset perturbation method. All the species are found to have a linear structure with a noble Gas–noble metal bond, the distance of which is closer to the respective covalent bond length in comparison with the relevant van der Waals limit. The dissociation energies corresponding to the lowest energy fragmentation products, MF+Ng, have been found to be in the range of −231 to −398kJ∕mol. The respective barrier heights pertinent to the bent transition states (M–Ng–F bending mode) are quite high for the CuXeF and AgXeF species, although for the Ar and Kr containing species the same are rather low. Nevertheless the M–Ng bond length in MNgF compounds reported here is the smallest M–Ng bond ever predicted through any experimental or theoretical investigation, indicating strongest M–Ng inte...
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Insertion of noble-Gas Atom (Kr and Xe) into noble-metal molecules (AuF and AuOH): are they stable?
The Journal of chemical physics, 2005Co-Authors: Tapan K. GhantyAbstract:The structure and the stability of a new class of insertion compounds of noble-Gas Atoms of the type AuNgX (Ng=Kr, Xe and X=F, OH) have been investigated theoretically through ab initio molecular-orbital calculations. All the species are found to have a linear structure with a noble-Gas-noble-metal bond, the distance of which is comparable to covalent bond length except the AuKrOH system, for which it lies in between the covalent and van der Waals limits. The dissociation energies corresponding to the lowest-energy fragmentation products, AuX+Ng have been computed to be -166.2, -276.0, -194.4, and -257.6 kJ/mol for AuXeF, AuKrF, AuXeOH, and AuKrOH, respectively, at the MP2 level of theory. The respective barrier heights corresponding to the bent transition states (Au-Ng-X bending mode) have been calculated to be 119.1, 74.9, 160.7, and 141.6 kJ/mol. However, three of these species are found to be metastable in their respective potential-energy surface, and the dissociation energies corresponding to the Au+Ng+X fragments have been calculated to be 112.9, 3.0, and 18.7 kJ/mol for AuXeF, AuKrF, and AuXeOH, respectively, at the same level of theory. An analysis of the nature of interactions involved in the Au-Ng-X systems has been performed using Bader's topological theory of Atoms-in-molecules (AIM). Geometric as well as energetic considerations along with AIM results suggest a partial covalent nature of Au-Ng bonds in these systems. This work might have important implications in the preparation of a new class of insertion compounds of noble-Gas Atoms containing noble-Gas-noble-metal bond.
Pratim Kumar Chattaraj - One of the best experts on this subject based on the ideXlab platform.
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noble noble strong union gold at its best to make a bond with a noble Gas Atom
ChemistryOpen, 2019Co-Authors: Sudip Pan, Pratim Kumar Chattaraj, Gourhari Jana, Gabriel MerinoAbstract:This Review presents the current status of the noble Gas (Ng)-noble metal chemistry, which began in 1977 with the detection of AuNe+ through mass spectroscopy and then grew from 2000 onwards; currently, the field is in a somewhat matured state. On one side, modern quantum chemistry is very effective in providing important insights into the structure, stability, and barrier for the decomposition of Ng compounds and, as a result, a plethora of viable Ng compounds have been predicted. On the other hand. experimental achievement also goes beyond microscopic detection and characterization through spectroscopic techniques and crystal structures at ambient temperature; for example, (AuXe4)2+(Sb2F11-)2 have also been obtained. The bonding between two noble elements of the periodic table can even reach the covalent limit. The relativistic effect makes gold a very special candidate to form a strong bond with Ng in comparison to copper and silver. Insertion compounds, which are metastable in nature, depending on their kinetic stability, display an even more fascinating bonding situation. The degree of covalency in Ng-M (M=noble metal) bonds of insertion compounds is far larger than that in non-insertion compounds. In fact, in MNgCN (M=Cu, Ag, Au) molecules, the M-Ng and Ng-C bonds might be represented as classical 2c-2e σ bonds. Therefore, noble metals, particularly gold, provide the opportunity for experimental chemists to obtain sufficiently stable complexes with Ng at room temperature in order to characterize them by using experimental techniques and, with the intriguing bonding situation, to explore them with various computational tools from a theoretical perspective. This field is relatively young and, in the coming years, a lot of advancement is expected experimentally as well as theoretically.
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stable ncngnsi ng kr xe rn compounds with covalently bound c ng n unit possible isomerization of ncnsi through the release of the noble Gas Atom
Chemistry: A European Journal, 2018Co-Authors: Sudip Pan, Gourhari Jana, Gabriel Merino, Estefania Ravell, Ximena Zarate, Edison Osorio, Pratim Kumar ChattarajAbstract:Although the noble Gas (Ng) compounds with either Ng-C or Ng-N bonds have been reported in the literature, compounds containing both bonds are not known. The first set of systems having a C-Ng-N bonding unit is predicted herein through the analysis of stability and bonding in the NCNgNSi (Ng=Kr-Rn) family. While the Xe and Rn inserted analogues are thermochemically stable with respect to all dissociation channels, but for the one producing CNSiN and free Ng, NCKrNSi has another additional three-body dissociation channel, NCKrNSi→CN+Kr+NSi, which is exergonic by -9.8 kcal mol-1 at 298 K. This latter dissociation can be hindered by lowering the temperature. Moreover, the NCNgNSi→Ng+CNSiN dissociation is also kinetically prohibited by a quite high free energy barrier ranging from 25.2 to 39.3 kcal mol-1 , with a gradual increase in going from Kr to Rn. Therefore, these compounds are appropriate candidates for experimental realization. A detailed bonding analysis by employing natural bond orbital, electron density, energy decomposition, and adaptive natural density partitioning analyses indicates that both Ng-N and C-Ng bonds in the title compounds are covalent in nature. In fact, the latter analysis indicates the presence of delocalized 3c-3e σ-bond within the C-Ng-N moiety and a totally delocalized 5c-2e σ-bond in these compounds. This is an unprecedented bonding characteristic in the sense that the bonding pattern in Ng inserted compounds is generally represented as the presence of covalent bond in one side of Ng, and the ionic interaction in the other side. Further, the dissociation of Ng from NCNgNSi facilitates the formation of a higher energy isomer of NCNSi, CNSiN, which cannot be formed from bare NCNSi as such, because of the very high free energy barrier associated with the isomeric transformation. Therefore, in the presence of Ng Atoms it might be possible to detect the high energy isomer.
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in quest of a superhalogen supported covalent bond involving a noble Gas Atom
Journal of Physical Chemistry A, 2015Co-Authors: Debdutta Chakraborty, Pratim Kumar ChattarajAbstract:The possibility of having neutral Xe-bound compounds mediated by some representative transition metal fluorides of general formula MX3 (where M=Ru, Os, Rh, Ir, Pd, Pt, Ag, Au and X=F) has been investigated through density functional theory based calculations. Nature of interaction between MX3 and Xe moieties has been characterized through detailed electron density, charge density and bond energy decomposition analyses. The feasibility of having compounds of general formula XeMX3 at 298 K has been predicted through thermodynamic considerations. The nature of interaction in between Xe and M Atoms is partly covalent in nature and the orbital interaction is the dominant contributor toward these interactions as suggested by energy decomposition analysis.
Markku Rasanen - One of the best experts on this subject based on the ideXlab platform.
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noble Gas hydrides new chemistry at low temperatures
Accounts of Chemical Research, 2009Co-Authors: Leonid Khriachtchev, Markku Rasanen, Benny R GerberAbstract:Noble-Gas chemistry has been undergoing a renaissance in recent years, due in large part to noble-Gas hydrides, HNgY, where Ng = noble-Gas Atom and Y = electronegative fragment. These molecules are exceptional because of their relatively weak bonding and large dipole moments, which lead to strongly enhanced effects of the environment, complexation, and reactions. In this Account, we discuss the matrix-isolation synthesis of noble-Gas hydrides, their spectroscopic and structural properties, and their stabilities. This family of species was discovered in 1995 and now has 23 members that are prepared in noble-Gas matrices (HXeBr, HKrCl, HXeH, HXeOH, HXeO, etc.). The preparations of the first neutral argon molecule, HArF, and halogen-free organic noble-Gas molecules (HXeCCH, HXeCC, HKrCCH, etc.) are important highlights of the field. These molecules are formed by the neutral H + Ng + Y channel. The first addition reaction involving HNgY molecules was HXeCC + Xe + H → HXeCCXeH, and this led to the first hydrid...
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formation of noble Gas hydrides and decay of solvated protons revisited diffusion controlled reactions and hydrogen Atom losses in solid noble Gases
Physical Chemistry Chemical Physics, 2008Co-Authors: Hanna Tanskanen, Leonid Khriachtchev, Markku Rasanen, Antti Lignell, Susanna Johansson, I V Khyzhniy, E V SavchenkoAbstract:UV photolysis and annealing of C2H2/Xe, C2H2/Xe/Kr, and HBr/Xe matrices lead to complicated photochemical processes and reactions. The dominating products in these experiments are noble-Gas hydrides with general formula HNgY (Ng = noble-Gas Atom, Y = electronegative fragment). We concentrate on distinguishing the local and global mobility and losses of H Atoms, barriers of the reactions, and the decay of solvated protons. Different deposition temperatures change the amount of lattice imperfections and thus the amount of traps for H Atoms. The averaged distance between reacting species influencing the reaction kinetics is controlled by varying the precursor concentration. A number of solid-state processes connected to the formation of noble-Gas hydrides and decay of solvated protons are discussed using a simple kinetic model. The most efficient formation of noble-Gas hydrides is connected with global (long-range) mobility of H Atoms leading to the H + Xe + Y reaction. The highest concentration of noble-Gas hydrides was obtained in matrices of highest optical quality, which probably have the lowest concentration of defects and H-Atom losses. In matrices with high amount of geometrical imperfections, the product formation is inefficient and dominated by a local (short-range) process. The decay of solvated protons is rather local than a global process, which is different from the formation of noble-Gas molecules. However, the present data do not allow distinguishing local proton and electron mobilities. Our previous results indicate that these are electrons which move to positively-charged centers and neutralize them. It is believed that the image obtained here for solid xenon is applicable to solid krypton whereas the case of argon deserves special attention.
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infrared absorption spectrum of matrix isolated noble Gas hydride molecules fingerprints of specific interactions and hindered rotation
Journal of Chemical Physics, 2005Co-Authors: Leonid Khriachtchev, Markku Rasanen, Antti Lignell, Jonas Juselius, E V SavchenkoAbstract:Noble-Gas hydride molecules with the general formula HNgY (Ng denotes noble-Gas Atom and Y denotes electronegative fragment) are usually prepared in solid noble Gases. In many cases, the matrix-isolated HNgY molecules show a characteristic structure of the H–Ng stretching absorption: A close doublet as the main spectral feature and a weaker satellite at higher energy. This characteristic band structure is studied here for matrix-isolated HXeBr and HKrCl molecules. Based on the experimental and theoretical results, we suggest a model explaining the common features of the band structure of the HNgY molecules in noble-Gas matrices. In this model, the main doublet bands are attributed to matrix sites where the splitting is caused by specific interactions of the embedded molecule with noble-Gas matrix Atoms in certain local morphology. The weaker blueshifted band is probably a fingerprint of hindered rotation (libration) of the embedded molecule in the lattice. This librational band has a mirror counterpart at...
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neutral rare Gas containing charge transfer molecules in solid matrices i hxecl hxebr hxei and hkrcl in kr and xe
Journal of Chemical Physics, 1995Co-Authors: Mika Pettersson, Jan Lundell, Markku RasanenAbstract:Ultraviolet‐irradiation of hydrogen halide containing rare Gas matrices yields the formation of linear centrosymmetric cations of type (XHX)+, (X=Ar, Kr, Xe). Annealing of the irradiated doped solids produces, along with thermoluminescence, extremely strong absorptions in the 1700–1000 cm−1 region. Based on isotopic substitution and halogen dependence of these bands, the presence of hydrogen and halogen Atom(s) in these species is evident. In the present paper we show the participation of rare Gas Atom(s) in these new compounds. The evidence is based on studies of the thermally generated species in mixed rare Gas matrices. The new species are assigned as neutral charge‐transfer molecules HX+Y− (Y=halogen), and their vibrational spectra are discussed and compared with those calculated with ab initio methods. This is the first time hydrogen and a rare Gas Atom has been found to make a chemical bond in a neutral stable compound. The highest level ab initio calculations on the existence of compounds of type HXY corroborate the experimental observations. The mechanism responsible for the formation of these species is also discussed.
Jan Meisner - One of the best experts on this subject based on the ideXlab platform.
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vibrational analysis of methyl cation rare Gas Atom complexes ch3 rg rg he ne ar kr
Journal of Chemical Physics, 2019Co-Authors: Jan Meisner, Philipp P Hallmen, Johannes Kastner, Guntram RauhutAbstract:The vibrational spectra of simple CH3+-Rg (Rg = He, Ne, Ar, Kr) complexes have been studied by vibrational configuration interaction theory relying on multidimensional potential energy surfaces (PESs) obtained from explicitly correlated coupled cluster calculations, CCSD(T)-F12a. In agreement with experimental results, the series of rare Gas Atoms leads to rather unsystematic results and indicates huge zero point vibrational energy effects for the helium complex. In order to study these sensitive complexes more consistently, we also introduce configuration averaged vibrational self-consistent field theory, which is a generalization of standard vibrational self-consistent field theory to several configurations. The vibrational spectra of the complexes are compared to that of the methyl cation, for which corrections due to scalar-relativistic effects, high-order coupled-cluster terms, e.g., quadruple excitations, and core-valence correlation have explicitly been accounted for. The occurrence of tunneling splittings for the vibrational ground-state of CH3+-He has been investigated on the basis of semiclassical instanton theory. These calculations and a direct comparison of the energy profiles along the intrinsic reaction coordinates with that of the hydronium cation, H3O+, suggest that tunneling effects for vibrationally excited states should be very small.
