A new, accurate, global, mass-independent, first-principles potential energy surface (PES) is presented for the ground electronic state of the water molecule. The PES is based on 2200 energy points computed at the all-electron aug-cc-pCV6Z IC-MRCI(8,2) level of electronic structure theory and includes the relativistic one-electron massvelocity and Darwin corrections. For H2 O, the PES has a dis...

The study on local modes as a molecule's eigen-vibration is still an attracting topic [1,2]. However, a new trend becomes more popular: people are more interested in the vibration properties of molecules under interactions with external laser fields for practical usages such as bond-selective photodesorption [3, 4] and vibrationally mediated dissociation [ 5 7 ] . We have already studied the po...

Vibrational modes of molecules are fundamental properties determined by intramolecular bonding, atomic masses, and molecular geometry, and often serve as important channels for dissipation in nanoscale processes. Although single-molecule junctions have been used to manipulate electronic structure and related functional properties of molecules, electrical control of vibrational mode energies has...

The donor/acceptor energy mismatch and vibrational coupling strength dependences of interionic vibrational energy transfer kinetics in electrolyte aqueous solutions were investigated with ultrafast multiple-dimensional vibrational spectroscopy. An analytical equation derived from the Fermi's Golden rule that correlates molecular structural parameters and vibrational energy transfer kinetics was...

Transitions from normal-mode to local-mode states in the two bending oscillations of acetylene observed in spectroscopic studies, as well as the existence of localized vibrational states in vinylidene above the isomerization barrier to acetylene, are examined by constructing continuation/ bifurcation diagrams of periodic orbits on a global potential-energy surface. The principal families of per...

The Molecular structure, conformational stability and vibrational frequencies of succinonitrile NCCH2CH2CN have been investigated with ab initio and density functional theory (DFT) methods implementing the standard 6-311++G* basis set. The potential energy surfaces (PES) have been explored at DFT-B3LYP, HF and MP2 levels of theory. In agreements with previous experimental results, the molecule ...

We first review how to determine the rate of vibrational energy relaxation (VER) using perturbation theory. We then apply those theoretical results to the problem of VER of a CD stretching mode in the protein cytochrome c. We model cytochrome c in vacuum as a normal mode system with the lowest-order anharmonic coupling elements. We find that, for the “lifetime” width parameter γ = 3 ∼ 30 cm, th...

We report the 364-nm negative ion photoelectron spectra of CHX(2)(-) and CDX(2)(-), where X = Cl, Br, and I. The pyramidal dihalomethyl anions undergo a large geometry change upon electron photodetachment to become nearly planar, resulting in multiple extended vibrational progressions in the photoelectron spectra. The normal mode analysis that successfully models photoelectron spectra when geom...

Highly accurate quantum-mechanical calculations az presented for highly excited vibrational states of HzO. The vibration Hamiltonian operator Hvib for a nonlinear triatomic molecule is given in Radau coordinates. A direct product basis is chosen, and the Hvib matrix is evaluated in the discrete variable representation (DVR) for the symmetrized Radau coordinates. Vibrational eigenstates are comp...

The paper presents the results for water confined in a human breast cancerous tissue, a single stranded DNA, a double stranded DNA and in phospholipids (DPPC—D--Phosphatidylcholine, dipalmitoyl). The interfacial water in DNA and lipids is represented by a double band in the region of the OH stretching mode of water corresponding to the symmetric and asymmetric vibrational modes, in contrast to...