相关论文: Vibrational Spectra of the Azabenzenes Revisited: …
In a previous contribution (Mol. Phys. {\bf 103}, xxxx, 2005), we established the suitability of density functional theory (DFT) for the calculation of molecular anharmonic force fields. In the present work, we have assessed a wide variety…
Accurate quartic anharmonic force fields for CF$_4$ and SiF$_4$ have been calculated using the CCSD(T) method and basis sets of $spdf$ quality. Based on the {\it ab initio} force field with a minor empirical adjustment, the vibrational…
We present density functional perturbation theory for electric field perturbations and ultra-soft pseudopotentials. Applications to benzene and anthracene molecules and surfaces are reported as examples. We point out several issues…
Experimental vibrational spectra (Raman and infrared absorption) of berberine are obtained at room temperature. The vibrational spectra of berberine are calculated by the DFT method at the B3LYP/6-311++G(d,p) level. Based on the correlation…
Understanding the fundamental processes of light-matter interaction is important for detection of explosives and other energetic materials, which are active in the infrared and terahertz (THz) region. We report a comprehensive study on…
Aims. Infrared (IR) spectroscopy is a powerful tool to study molecules in space. A key issue in such analyses is understanding the effect that temperature and anharmonicity have on different vibrational bands, and thus interpreting the IR…
Experimental, theoretical, and additive-model photoabsorption cross-sections combined with constraints provided by the Kuhn-Reiche-Thomas sum rule and the high-energy behavior of the dipole-oscillator-strength density are used to construct…
TIn the first chapter, the current ideas about crystalline disordered system are surveyed and exemplified by the results allowing for the most straightforward interpretation. Exclusive consideration is intended for broadband dielectric…
We present large-scale density-functional theory (DFT) calculations and temperature programmed desorption measurements to characterize the structural, energetic and vibrational properties of the functionalized molecular switch…
Optical properties of symmetry-forbidden pi-pi transitions in benzene are calculated with the time-dependent density functional theory (TDDFT), using an adiabatic LDA functional. Quantities calculated are the envelopes of the Franck-Condon…
Density-functional theory may be used to predict both the frequency and the dipole moment of the fundamental oscillations of molecular crystals. Suitably polarized photons at those frequencies excite such oscillations. Thus, in principle,…
The very good performance of modern density functional theory for molecular geometries and harmonic vibrational frequencies has been well established. We investigate the performance of density functional theory (DFT) for quartic force…
Aims. In this work we determine the effects of anharmonicity on the mid-infrared spectra of the linear polycyclic aromatic hydrocarbons (PAHs) naphthalene, anthracene, tetracene and pentacene recorded using the free electron laser FELIX.…
The anharmonic phenomena in Zirconium Hydrides and Deuterides, including {\epsilon}-ZrH2, {\gamma}-ZrH, and {\gamma}-ZrD, have been investigated from aspects of inelastic neutron scattering (INS) and lattice dynamics calculations within the…
The spectral determinant $D(E)$ of the quartic oscillator is known to satisfy a functional equation. This is mapped onto the $A_3$-related $Y$-system emerging in the treatment of a certain perturbed conformal field theory, allowing us to…
The vibrationally resolved spectra of the pyrene cation and doubly-dehydrogenated pyrene cation (C$_{16}$H$_{10}$$^{.+}$; Py$^+$ and C$_{16}$H$_{8}$$^{.+}$; ddPy$^+$) are presented. Infrared predissociation spectroscopy is employed to…
Quantifying the effect of anharmonicity on the infrared spectrum of large molecules such as polycyclic aromatic hydrocarbons (PAHs) at high temperature is the focus of a number of theoretical and experimental studies, many of them motivated…
There is renewed interest in the structure of the essential amino acid Phenylalanine in the solid state. Three new polymorphs were found in the years 2012 to 2014. Here, we investigate the structure, stability, and energetical ordering of…
We present a hybrid CCSD(T)+PBE-D3 approach to calculating the vibrational signatures for gas phase benzene and benzene adsorbed on an ordered water-ice surface. We compare the results of our method against experimentally recorded spectra…
The paper analyses the SEHR spectra of symmetrical molecules on the base of the dipole-quadrupole SEHRS theory. Existence of the bands, caused by vibrations transforming after the unit irreducible representations of corresponding symmetry…