The vibrational configuration interaction method used to obtain static vibrational (hyper)polarizabilities is extended to dynamic nonlinear optical properties in the infinite optical frequency approximation. Illustrative calculations are carried out on H(2)O and NH(3). The former molecule is weakly anharmonic while the latter contains a strongly anharmonic umbrella mode. The effect on vibration...

We analyze experimentally and theoretically >1 GHz optoexcited mechanical vibration in an on-chip micron-scaled sphere. Different eigen-mechanical modes are excited upon demand by the centrifugal radiation pressure of the optical whispering-gallery-mode, enabling an optomechanical modal spectroscopy investigation of many vibrational modes. Spectral analysis of the light emitted from the device ...

Using polarization-selective two-dimensional infrared (2D IR) and infrared pump-probe spectroscopies, we study vibrational relaxation of the four cyanide stretching (νCN) vibrations found in [(NH3)5Ru(III)NCFe(II)(CN)5](-) (FeRu) dissolved in D2O or formamide and [(NC)5Fe(II)CNPt(IV)(NH3)4NCFe(II)(CN)5](4-) (FePtFe) dissolved in D2O. These cyanide-bridged transition metal complexes serve as mod...

Ultrafast two dimensional infrared (2D IR) spectroscopy has been applied to probe the intermolecular vibrational energy exchange between two model molecules, benzonitrile and acetonitrile-(d3). The vibrational energy exchange between these two molecules is manifested through the growth of cross peaks in their 2D IR spectra. In experiments, their nitrile groups (CN) are not involved in the energ...

We perform converged high precision variational calculations to determine the frequencies of a large number of vibrational levels in S(0) D(2)CO, extending from low to very high excess vibrational energies. For the calculations we use our specific vibrational method (recently employed for studies on H(2)CO), consisting of a combination of a search/selection algorithm and a Lanczos iteration pro...

We report real-time observation of the interlayer shearing mode, corresponding to the lateral oscillation of graphene planes, for bi- and few-layer graphene. Using a femtosecond pump-probe technique, we have followed coherent oscillations of this vibrational mode directly in the time domain. The shearing-mode frequency, as expected for an interlayer mode, exhibits a strong and systematic depend...

Excited-state vibrational coherence of solution-phase polyatomic molecules was studied by two different timedomain spectroscopic methods. Raman-active low-frequency vibrations in the excited state of trans-stilbene were observed by transient impulsive stimulated Raman scattering spectroscopy. In transient absorption spectroscopy with a 40-fs resolution, a different vibrational mode of the same ...

The mode-specific vibrational energy relaxation of the amide I' and amide II' modes in NMA-d(1)/(D(2)O)(n) (n = 0-3) clusters were studied using the time-dependent perturbation theory at the B3LYP/aug-cc-pvdz level. The amide modes were identified for each cluster based on the potential energy distribution of each mode. The vibrational population relaxation time constants were derived for the a...

We have developed a computational approach that yields anharmonic vibrational couplings in molecular crystals. The approach is based on anharmonic vibrational potential-energy surface reconstruction starting from a normal-mode vibrational basis. The method was implemented for semiempirical Hamiltonians with periodic boundary conditions, with applications to crystalline naphthalene and pentaeryt...

The second paper of the series discusses the effect of thermal noise on the stretching vibrational dynamics of symmetric triatomic ABA molecules. In particular, noise-induced transitions between symmetric and antisymmetric normal-mode vibrations are discussed, in the context of symmetry breaking of vibrational dynamics. The statistics of symmetry breaking transitions and the average lifetimes o...