Harmonic Oscillator Approximation Research Articles

Divergence of entanglement entropy in quantum systems: Zero-modes

To this day, von Neumann definition of entropy remains the most popular measure of quantum entanglement. Much of the literature on entanglement entropy, particularly in the context of field theory, has focused on isolating the UV divergences. Zero-mode divergences of the entanglement entropy are less studied in this context, and apart from being easier to isolate, they offer an interesting insight into the physics of the system. To gain a better understanding of the system in this limit, we develop the free particle approximation of Harmonic oscillator, with which we investigate the properties of entropy divergence in continuous bi-partite quantum systems such as the coupled Harmonic oscillators and the Hydrogen atom. We also show zero-mode divergence of the entropy of environment-induced entanglement in a tri-partite oscillator system. We discuss the implications of our result for field theory and IR structure of gravity.

Predicting Phosphorescence Rates of Light Organic Molecules Using Time-Dependent Density Functional Theory and the Path Integral Approach to Dynamics.

In this work, we present a general method for predicting phosphorescence rates and spectra for molecules using time-dependent density functional theory (TD-DFT) and a path integral approach for the dynamics that relies on the harmonic oscillator approximation for the nuclear movement. We first discuss the theory involved in including spin–orbit coupling (SOC) among singlet and triplet excited states and then how to compute the corrected transition dipole moments and phosphorescence rates. We investigate the dependence of these rates on some TD-DFT parameters, such as the nature of the functional, the number of roots, and the Tamm–Dancoff approximation. After that, we evaluate the effect of different SOC integral schemes and show that our best method is applicable to a large number of systems with different excited state characters.

Van der Waals interaction of ground state energy on ion molecular Hidrogen H2+

Hydrogen molecular ions are formed from Hydrogen molecules (H2) that lose one electron due to a particular process, such as ionization. H2+ is a ionic molecule and one of the interstellar molecules. When H2+vibrates, inter-core interactions will occur. The interaction takes place from between the point dipole and the farthest proton. These interactions are called Van der Waals interactions. Van der Waals interaction is one of the interactions that occur in H2+, in addition to ionisation energy. The presence of van der Waals interactions on H2+ will produce a certain energy whose value is small. In previous research, it has been shown that Van der Waals interaction will decrease the energy value of solid and liquid structures. In this research, we calculate energy on ion molecular hidrogen H2+ as a second order perturbation theory. Using data from Herzberg, the n = 0 vibrational energy level with harmonic oscillator approximation was obtained corresponding to Born-Oppenheimer potential. Based on perturbation theory, the vibrational energy varies with the order ofR−4 The simulations of vibrational wave functions both unperturbed and perturbed by van der Waals interaction show that difference between them is not significant. In particular, it is shown that the van der Waals interaction influence the shifting of the equilibrium point of H2+ which depends on the parameter and internuclear separation. Ground state energy on ion molecular Hidrogen H2+ in van der walls interaction is 0.087664 eV to 0.140693 eV

Crystalline splitting of d orbitals in two-dimensional regular optical lattices

In solids, crystal field splitting refers to the lifting of atomic orbital degeneracy by the surrounding ions through the static electric field. Similarly, we show that the degenerated $d$ orbitals, which were derived in the harmonic oscillator approximation, are split into a low-lying $d_{x^2+y^2}$ singlet and a $d_{x^2-y^2/xy}$ doublet by the high-order Taylor polynomials of triangular optical potential. The low-energy effective theory of the orbital Mott insulator at $2/3$ filling is generically described by the Heisenberg-Compass model, where the antiferro-orbital exchange interactions of compass type depend on the bond orientation and are geometrically frustrated in the triangular lattice. While, for the square optical lattice, the degenerated $d$ orbitals are split into a different multiplet structure, i.e. a low-lying $d_{x^2\pm y^2}$ doublet and a $d_{xy}$ singlet, which has its physical origin in the $C_{4v}$ point group symmetry of square optical potential. Our results build a novel bridge between ultracold atom systems and solid-state systems for the investigation of $d$-orbital physics.

Spectroscopic ellipsometry study of TlGaSeS layered crystal

The optical properties of TlGaSeS at room temperature in the 0.96–5.05 eV photon-energy range has been investigated using variable angle spectroscopic ellipsometry (VASE). The obtained results of dielectric spectra data display different structures at critical points energies. The results are analyzed with reference to three models of the interband transitions in crystal semiconductors, namely, harmonic oscillator approximation (HOA), standard critical-point (SCP) model and critical-point parabolic-band (CPPB). Results are in plausible agreement with the both SCP and CPPB computations over the whole range of the photon wavelengths. Dielectric- correlated optical parameters of TlGaSeS, such as the absorption coefficient, the refractive index, and the orthogonal-incidence reflectivity are illustrated and investigated.

Thermodynamic properties of Si(OH)4(g) based on combined experimental and quantum chemistry data

AbstractThe volatility of silicon‐based ceramics in combustion environments is primarily controlled by the formation of gaseous Si(OH)4. The heat capacities and entropies of this species at 298.15‐2100 K and P = 0.1 MPa have been studied with the B3LYP density functional theory for the 6‐311+G(d,p) basis set in different approximations: a harmonic oscillator, an anharmonic oscillator, and with corrections for hindered rotors. Experimentally based Gibbs energies of Si(OH)4(g) at 424‐1661 K have been employed to evaluate the Gibbs energy of formation, , and the entropy, , of Si(OH)4(g) at = 298.15 K and P = 0.1 MPa. We found that the QC and “experimental” values are very close for the harmonic and anharmonic oscillator approximations, but not for the “hindered rotor” approximation. This conclusion is also supported by calculations of the OH rotational energy for Si(OH)4 molecule, where the potential barrier was found to exceed 12 kJ/mol. Finally, we recommend the thermodynamic properties of Si(OH)4 in the ideal gas state at P = 0.1 MPa over the temperature range of 298‐2100 K.

Q2DTor: A program to treat torsional anharmonicity through coupled pair torsions in flexible molecules

The Q 2DTor program (Quantum 2-Dimensional Torsions) is designed to calculate accurate rotational–vibrational partition functions (also called rovibrational partition functions) and thermodynamic functions for molecular systems having two [1] or more torsions. Systems with more than two torsions can also be studied by treating the torsions by pairs. The program searches for all the torsional conformers and evaluates the rovibrational partition function using the multi-structural harmonic oscillator (MS-HO) approximation and the extended two-dimensional torsion (E2DT) approximation. The latter incorporates full coupling of the two torsions by means of the two-dimensional non-separable (2D-NS) approximation [2], and it also includes their influence on the remaining degrees of freedom. The program also calculates the ideal gas-phase standard-state thermodynamic functions at the requested temperatures. Twenty molecules have been used to test Q 2DTor. Program summaryProgram Title:Q2DTorProgram Files doi:http://dx.doi.org/10.17632/wbgchgc2kp.1Licensing provisions: GNU GPL v3Programming language: Python 2.7Nature of problem: Calculation of accurate partition functions and thermodynamic functions in molecular systems involving two torsional modes. Torsional anharmonicity is treated quantically and includes full coupling in the kinetic and potential energies between the torsions and between the torsions and the rest of the degrees of freedom.Solution method: The program uses the variational method to solve the Schrödinger equation of a two-dimensional torsional potential using Fourier series. All of the remaining degrees of freedom (non-torsional) are incorporated through a projected (the torsional modes are removed) rigid-rotator harmonic-oscillator partition function which is calculated at every torsional stationary point and that is allowed to vary with the torsional motion. The integration of the rovibrational partition function over the torsional space leads to a mixed quantum-classical vibrational partition function, which is transformed into a full quantum partition function by including the quantum contribution due to the torsions. For the evaluation of the integral, the rovibrational partition function at nonstationary points is carried out through a Delaunay triangulation procedure using the calculated rovibrational partition functions at the stationary points as nodes.Additional comments including Restrictions and Unusual features: The program is limited to two coupled torsional modes.

Single-particle spatial dispersion and clusters in nuclei

The spatial dispersion of the single-nucleon wave functions is analyzed using the self-consistent mean-field framework based on nuclear energy density functionals, and with the harmonic oscillator approximation for the nuclear potential. It is shown that the dispersion depends on the radial quantum number n, but displays only a very weak dependence on the orbital angular momentum. An analytic expression is derived for the localization parameter that explicitly takes into account the radial quantum number of occupied single-nucleon states. The conditions for single-nucleon localization and formation of cluster structures are fulfilled in relatively light nuclei with $A \leq 30$ and $n=1$ states occupied. Heavier nuclei exhibit the quantum liquid phase of nucleonic matter because occupied levels that originate from $n > 1$ spherical states are largely delocalized. Nevertheless, individual $\alpha$-like clusters can be formed from valence nucleons filling single-particle levels originating from $n=1$ spherical mean-field states.

Structural and thermochemical properties of methyl ethyl sulfide alcohols: HOCH2SCH2CH3, CH3SCH(OH)CH3, CH3SCH2CH2OH, and radicals corresponding to loss of H atom

AbstractSulfide alkoxy radicals are important intermediates during the partial oxidation of alkyl sulfides in atmospheric chemistry and in combustion. The atmospheric reaction sequence to formation of the alkoxy radicals includes (1) initial reaction with OH to create a radical on a carbon site, (2) the carbon radical then associates with 3O2 to form a peroxy radical, and (3) an NO radical reacts with the peroxy radical to form an alkoxy radical (RO•) plus NO2. This study determines structural parameters, internal rotor potentials, bond dissociation energies, and thermochemical properties (ΔfH°, S°, and Cp(T)) of 3 corresponding alcohols HOCH2SCH2CH3, CH3SCH(OH)CH3, and CH3SCH2CH2OH of methyl ethyl sulfides studied in order to characterize the thermochemistry of the respective alkoxy radicals. The lowest energy molecular structures were calculated using the B3LYP density functional level of theory with the 6‐311G(2d,d,p) basis set. Standard enthalpies of formation (ΔfH°298) for the radicals and their parent molecules were calculated using B3LYP/6‐31 + G(2d,p), CBS‐QB3, M062x/6‐311 + g(2d,p), and G3MP2B3 methods. Isodesmic reactions were used to determine ∆fH° values. Internal rotation potential energy diagrams and rotation barriers were investigated using the B3LYP/6‐31 + G(d,p) level theory. The contributions for S°298 and Cp(T) were calculated using the rigid rotor harmonic oscillator approximation based on the structures and vibrational frequencies obtained by CBS‐QB3 calculations, with contributions from torsion frequencies replaced by internal rotor contributions. Group additivity and hydrogen bond increment values were developed for estimating properties of structurally similar and larger sulfur‐containing peroxide molecules and their radicals.

Broadband Terahertz Spectroscopy of Imidazolium-Based Ionic Liquids.

Ionic liquids are liquid salts at ambient temperature composed of organic cations and organic/inorganic anions. Outstanding physical and chemical properties of ionic liquids lead to increasing application in scientific and industrial field. Ionic liquids have been already investigated by different spectroscopic techniques, including terahertz (THz) time-domain spectroscopy. The usual THz frequency range extends up to 2-3 THz, a relatively narrow band, which can only show the intermolecular vibrational modes. Here, we report about broadband THz spectroscopy of ionic liquids up to 13 THz. Bandwidth of intermolecular absorption band presents an unexpected behavior and strong sharp intramolecular absorptions are shown. In addition, we found violation of the approximation of harmonic oscillator used to predict the peak shift of intermolecular absorption band.

A theoretical explanation of RbBH4’s fractionally occupied ground-state phase and the reorientational motion of the [BH4]− group

In this work, a pseudo-structure model is adopted to describe the fractionally occupied phase of RbBH4 at low temperatures. The fractionally occupied cubic ground state with Fm3m symmetry can be explained as a superposition and average of three well-defined pseudo-structures with P43m, F43m and P42/nmc symmetries. First, both mechanical and dynamical stability of these pseudo-structures are supported by the calculated elastic constants and phonon spectra, respectively. By comparing the electronic structure, elastic properties and thermodynamic properties of these well-defined pseudo-structures, it can be found that all pseudo-structures exhibit a certain degree of similarity. Second, the system is stabilized by charge transfer. Bader charge analysis of the pseudo-structures shows that charge transfer in RbBH4 contributes a constant shift in formation energy. Coulomb interaction energy and total electronic energy variations with the unit cell volume have been obtained. The results show that the larger the volume of the unit cell, the lower the difference of Coulomb interaction energy between the pseudo-structures P43m, F43m and P42/nmc. Third, the barrier energies calculated for paths of transitions between these pseudo-structures vary significantly with the volume. As the cell volume decreases from 512 to 216 Å3, the B–H covalent bonds are compressed from 1.242 to 1.208 Å. Meanwhile, the rotational barrier of [BH4]− anion increases rapidly, from 0.04 to 0.97 eV. Last, considering the temperature effect, the free energy and entropy contributions are calculated based on the rigid rotor harmonic oscillator approximation. The Gibbs free energy shows that at low temperature the P42/nmc structure is the preferred structure, and with increasing temperature, the P43m structure becomes the preferred structure. We found that the fractionally occupied phase of RbBH4 can be explained by the size of the Rb+ cation and a subtle balance between the Coulomb interaction energy, electronic total energy and thermal vibration energy.

Molecular structure, nonlinear optical studies and spectroscopic analysis of chalcone derivative (2E)-3-[4-(methylsulfanyl) phenyl]-1-(3-bromophenyl) prop-2-en-1-one by DFT calculations

A collective experimental and theoretical study was conducted on the molecular structure and vibrational spectra of nonlinear optical chalcone derivative (2E)-3-[4-(methylsulfanyl) phenyl]-1-(3-bromophenyl) prop-2-en-1-one (3Br4MSP). The FT-IR and FT-Raman spectra of the molecule in the solid phase have been recorded. Density functional theory (DFT) calculations at B3LYP level with 6–311++G (d,p) basis set have been carried out to derive useful information about the molecular structure and to assign the relevant electronic and vibrational features. These calculations reveal that the optimized geometry closely resembles the experimental XRD data. The vibrational spectra were analyzed on the basis of the potential energy distribution (PED) of each vibrational mode, which allowed us to obtain a quantitative as well as qualitative interpretation of FT-IR and FT-Raman spectra. The UV–vis spectrum was recorded in methanol solution. The excited state properties have been determined by TD-DFT method and the effect of solvent was analyzed by PCM model. The most prominent transition corresponds to π→π∗. The reactivity parameters as chemical potential, global hardness, and electrophilicity index have also been calculated. To provide an explicit assignment and analysis of 13C and 1H NMR spectra, theoretical calculations on chemical shift of the title compound were done through GIAO method at B3LYP/6-311++G (d,p) level. The Mulliken's population analysis shows one of the simplest pictures of charge distribution. The standard statistical thermodynamic functions like heat capacity at constant pressure (Cop,m), entropy (Som) and enthalpy (Hom) were obtained from the theoretical harmonic frequencies for the optimized molecule. The nonlinear optical properties of title molecule are also addressed theoretically. Two contributions, vibrational and electronic, to the electrical properties polarizability and first order hyperpolarizability of 3Br4MSP have been evaluated using the self-consistent field wave functions within the double harmonic oscillator approximation.

Structures and thermochemistry of methyl ethyl sulfide and its hydroperoxides: HOOCH2SCH2CH3, CH3SCH(OOH)CH3, CH3SCH2CH2OOH, and radicals

AbstractHydroperoxides and the corresponding peroxy radicals are important intermediates during the partial oxidation of methyl ethyl sulfide (CH3SCH2CH3) in both atmospheric chemistry and in combustion. Structural parameters, internal rotor potentials, bond dissociation energies, and thermochemical properties (ΔHfo, So and Cp(T)) of 3 corresponding hydroperoxides CH2(OOH)SCH2CH3, CH3SCH(OOH)CH3, CH3SCH2CH2OOH of methyl ethyl sulfides, and the radicals formed via loss of a hydrogen atom are important to understanding the oxidation reactions of MES. The lowest energy molecular structures were identified using the density functional B3LYP/6‐311G(2d,d,p) level of theory. Standard enthalpies of formation (ΔHfo298) for the radicals and their parent molecules were calculated using the density functional B3LYP/6‐31G(d,p), B3LYP/6‐31 + G(2d,p), and the composite CBS‐QB3 ab initio methods. Isodesmic reactions were used to determine ∆Hfo values. Internal rotation potential energy diagrams and rotation barriers were investigated using the B3LYP/6‐31G(d,p) level theory. Contributions for So298 and Cp(T) were calculated using the rigid rotor harmonic oscillator approximation based on the structures and vibrational frequencies obtained by the density functional calculations, with contributions from torsion frequencies replaced by internal rotor contributions. The recommended values for enthalpies of formation of the most stable conformers of CH3SCH2CH2, CH2(OOH)SCH2CH3, CH3SCH(OOH)CH3, and CH3SCH2CH2OOH are −14.0, −33.0, −37.2, and −32.7 kcal/mol, respectively. Group additivity values were developed for estimating properties of structurally similar and larger sulfur‐containing peroxides. Groups for use in group additivity estimation of sulfur peroxide thermochemical properties were developed.

Reaction Ensemble Monte Carlo Simulation of Xylene Isomerization in Bulk Phases and under Confinement.

The original reaction move for the reaction ensemble Monte Carlo (RxMC) method is adapted to align both the position and orientation of inserted product molecules and deleted reactant molecules. The accuracy and efficiency of this move is demonstrated for xylene isomerization in vapor, liquid, and supercritical phases. Classical RxMC requires the ideal gas free energy of reaction ΔGrxnideal as an input. We compare three methods for computing ΔGrxnideal: using tabulated enthalpies and entropies of formation, using the harmonic oscillator and rigid rotor approximations and using QM/MM alchemical transformation combined with multistate Bennett acceptance ratio. We find that the tabulated free energies of reaction give the best agreement with experimental equilibrium compositions in bulk fluids. RxMC simulations in a carbon nanotube with an inner diameter of approximately 6 Å show that p-xylene becomes the dominant isomer under confinement, an effect consistent with the production of p-xylene in the zeolite ZSM-5. We also show that o-xylene becomes the dominant isomer in nanotubes with an inner diameter of 7-8 Å. We find that both m- and p-xylene exhibit a loss of rotational entropy in nanotubes of this diameter, effectively allowing o-xylene to fit into cavities inaccessible to the other isomers.

Anharmonicity of Coupled Torsions: The Extended Two-Dimensional Torsion Method and Its Use To Assess More Approximate Methods.

In this work we present the extended two-dimensional torsion (E2DT) method and use it to analyze the performance of several methods that incorporate torsional anharmonicity more approximately for calculating rotational-vibrational partition functions. Twenty molecules having two hindered rotors were studied for temperatures between 100 and 2500 K. These molecules present several kinds of situations; they include molecules with nearly separable rotors, molecules in which the reduced moments of inertia change substantially with the internal rotation, and molecules presenting compound rotation. Partition functions obtained by the rigid-rotor harmonic oscillator approximation, a method involving global separability of torsions and the multistructural methods without explicit potential coupling [MS-T(U)] and with explicit potential coupling [MS-T(C)] of torsions, are compared to those obtained with a quantized version - called the extended two-dimensional torsion (E2DT) method - of the extended hindered rotor approximation of Vansteenkiste et al. ( Vansteenkiste et al. J. Chem. Phys. 2006 , 124 , 044314 ). In the E2DT method, quantum effects due to the torsional modes were incorporated by the two-dimensional nonseparable method, which is a method that is based on the solution of the torsional Schrödinger equation and that includes full coupling in both the kinetic and potential energy. By comparing other methods to the E2DT method and to experimental thermochemical data, this study concludes that the harmonic approximation yields very poor results at high temperatures; the global separation of torsions from the rest of the degrees of freedom is not justified even when an accurate method to treat the torsions is employed; it is confirmed that methods based on less complete potential energy coupling of torsions, such as MS-T(U), are not accurate when dealing with rotors with different barrier heights, and more complete inclusion of torsional coupling to the method in MS-T(C) improves substantially the results in such a way that it could be used in cases where the E2DT method is unaffordable.

Tunable optical properties of co-sputtered Ti-SiO_2 nanocomposite thin films

In this work, optical constants of direct current (DC) and radio frequency (RF) co-sputtered Ti-SiO2 nanocomposite thin films were investigated and tuned by controlling the deposition power of Ti in the SiO2 host matrix. X-ray photoelectron spectroscopy (XPS) results confirmed that the metallic Ti was completely oxidized into different titanium oxide states while the Si4+ state was reduced to the Si2+ or Si0 state by observing the Ti 2p, O 1s and Si 2p line shapes changing under different deposition conditions. The optical constants of the composites were characterized with a spectroscopic ellipsometer (SE) and reduced by using the modified harmonic oscillator approximation (HOA) model. The results show that the metal-dielectric nanocomposite will have an advantage over natural materials because its optical properties of n and k can be properly tuned by adjusting the concentration of Ti in the Ti-SiO2 nanocomposites, thus satisfying the requirements of photonic device design and applications in broad spectral regions.

STATTHERMO® – NEW SOFTWARE FOR CALCULATION OF THERMODYNAMIC FUNCTIONS

A new software StatThermo for calculation of thermodynamic functions using the molecular constants in Rigid Rotator – Harmonic Oscillator approximation has been developed. Program includes various prebuilt algorithms to calculate atom coordinates for the majority of simple compounds (with a number of atoms N ≤ 8). The developed software can make the calculation for two reference temperatures (0 or 298.15 K) and different pressures. One of the prominent features of StatThermo is taking into account the low-lying electronic levels. The software was tested on different organic and inorganic molecules and average errors was found as follows: 0.05 kJ∙mol–1 (H°(T)-H°(0)), 0.01 J∙mol–1∙K–1 (Ф°(T)), and 0.002 J∙mol–1∙K–1 (S°(T)). The program can also approximate by the polynomial the thermodynamic functions defined by user. A wide range of functional possibilities, flexible parameters of calculation, and feature of export results in the Visual Basic macro do the StatThermo powerful software for thermodynamic computations. StatThermo can connect to the MS Office and OpenOffice servers for the export of calculated data. The software can treat the Gaussian, Gamess, FireFly, Jaguar, MolPro, CFour, NWChem, ORCA, Priroda, PSI4, Q-Chem, and VASP output files. A multilingual and cross-platform support makes the StatThermo accessible for a lot of users. Forcitation:Dunaev A.M., KudinL.S. StatThermo® – new software for calculation of thermodynamic functions. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 4. P. 40-46.

Hamiltonian approach to GR \u2013 Part 2: covariant theory of quantum gravity

A non-perturbative quantum field theory of General Relativity is presented which leads to a new realization of the theory of covariant quantum gravity (CQG-theory). The treatment is founded on the recently identified Hamiltonian structure associated with the classical space-time, i.e., the corresponding manifestly covariant Hamilton equations and the related Hamilton–Jacobi theory. The quantum Hamiltonian operator and the CQG-wave equation for the corresponding CQG-state and wave function are realized in 4-scalar form. The new quantum wave equation is shown to be equivalent to a set of quantum hydrodynamic equations which warrant the consistency with the classical GR Hamilton–Jacobi equation in the semiclassical limit. A perturbative approximation scheme is developed, which permits the adoption of the harmonic oscillator approximation for the treatment of the Hamiltonian potential. As an application of the theory, the stationary vacuum CQG-wave equation is studied, yielding a stationary equation for the CQG-state in terms of the 4-scalar invariant-energy eigenvalue associated with the corresponding approximate quantum Hamiltonian operator. The conditions for the existence of a discrete invariant-energy spectrum are pointed out. This yields a possible estimate for the graviton mass together with a new interpretation about the quantum origin of the cosmological constant.

An Efficient Analytic Approach for Calculation of Multi-Dimensional Franck-Condon Factors and Associated Photoelectron Spectra.

The implementation, optimization, and performance of a generalized analytic treatment of multidimensional Franck-Condon Factors (FCF) within the harmonic oscillator approximation and associated photoelectron spectra (PES) for N-dimensional systems, including consideration of Eckart conditions in the displacement minimization and Cartesian coordinate handedness for evaluation of the Duschinsky Effect, is carried out in this work. A new efficient strategy for algorithmic efficiency for high dimensional systems is introduced, and demonstrated for 3-, 15-, and 30-dimensional systems. Determination of the photoelectron spectra for H2O+ (B̃2B2), vinyl alcohol, and C6H6+ (X̃2E1g) validates the capabilities with a high degree of accuracy with respect to experiment.

Thermodynamic functions of germanium oxide molecules in the gaseous phase: GeO2(g), Ge2O2(g), and Ge3O3(g)

Critical analysis of experimental and theoretical data on the structure and vibrational frequencies of GeO2, Ge2O2, and Ge3O3 molecules is performed. The values of molecular constants are chosen, and thermodynamic functions in the rigid rotator–harmonic oscillator approximation are calculated in temperature interval Т = 298.15–3000 K. The values obtained are introduced into the data base of the IVTANTERMO program complex.