Quantum state resolved reactivity measurements probe the role of vibrational symmetry on the vibrational activation of the dissociative chemisorption of CH4 on Ni(111). IR-IR double resonance excitation in a molecular beam was used to prepare CH4 in three different vibrational symmetry components, A1, E, and F2, of the 2ν3 antisymmetric stretch overtone vibration as well as in the ν1+ν3 symmetr...

A full-dimensional Franck-Condon calculation has been applied to the à (1)Au-X̃ 1Σg+ transition in acetylene in the harmonic normal mode basis. Details of the calculation are discussed in Part I of this series. To our knowledge, this is the first full-dimensional Franck-Condon calculation on a tetra-atomic molecule undergoing a linear-to-bent geometry change. In the current work, the vibrational...

Recent modeling of thermal nonequilibrium processes in simple molecules like hydrogen and nitrogen has indicated that rotational nonequilibrium becomes as important as vibrational nonequilibrium at high temperature. In this study, to analyze rotational nonequilibrium, the rotational mode is separated from the translational-rotational mode that is usually considered in two-temperature models. Th...

Using analytical excited-state gradients, vibrational normal modes have been calculated at the minimum of the electronic excited-state potential energy surfaces for a set of extended conjugated molecules with different coupling between them. Molecular model systems composed of units of polyphenylene ethynylene (PPE), polyphenylenevinylene (PPV), and naphthacene/pentacene (NP) have been consider...

We have refined vibrational force fields for polypeptides that permit excellent reproduction of the normal mode frequencies of such molecules. This is demonstrated in the present study, in which 80 IR and Raman bands of crystalline triglycine between 1800 and 200 cm-’ are reproduced with an average error of 6 cm-‘. A deuterated sample is shown by normal mode analysis to have remained protonated...

Femtosecond vibrational coherence spectroscopy is used to investigate the low frequency vibrational dynamics of the electron transfer heme protein, cytochrome c (cyt c). The vibrational coherence spectra of ferric cyt c have been measured as a function of excitation wavelength within the Soret band. Vibrational coherence spectra obtained with excitation between 412 and 421 nm display a strong m...

The calculation of thermochemical data requires accurate molecular energies and heat capacities. Traditional methods rely upon the standard harmonic normal-mode analysis to calculate the vibrational and rotational contributions. We utilize path-integral Monte Carlo for going beyond the harmonic analysis and to calculate the vibrational and rotational contributions to ab initio energies. This is...

A computational approach to describe the energy relaxation of a high-frequency vibrational mode in a fluctuating heterogeneous environment is outlined. Extending previous work [H. Fujisaki, Y. Zhang, and J. E. Straub, J. Chem. Phys. 124, 144910 (2006)], second-order time-dependent perturbation theory is employed which includes the fluctuations of the parameters in the Hamiltonian within the vib...

Vibrational dynamics of folded proteins is studied using a Gaussian model in which the protein is viewed as a network, residues representing the junctions, and the connectivity being established by a single parameter harmonic potential. Application to seven proteins showed that the local packing density plays a major role in determining the vibrational spectrum at time scales of picoseconds. At...

We have applied nuclear inelastic scattering (NIS) and computational predictions based on density functional theory (DFT) to explore the vibrational dynamics of Fe in a trinuclear oxo-bridged iron(III) complex. Quantitative comparison of the experimentally measured vibrational dynamics of the Mössbauer nuclei Fe, with normal mode analysis, calculated via quantum chemical calculation based on DF...