The interaction between localized and extended vibrational modes in solids is of central importance in understanding how local vibrational modes decay into phonons. Interstitial oxygen (O(i)) in silicon is a model system for studying such interactions. Using hydrostatic pressure, we have brought the antisymmetric stretch mode of (18)O(i) in silicon into resonance with the second harmonic of the...

In this paper, the radial breathing mode (RBM) frequencies of multi-walled carbon nanotubes (MWCNTs) are  obtained based on the multiple-elastic thin shell model. For this purpose, MWCNT is considered as a multiple concentric elastic thin cylindrical shells, which are coupled through van der Waals (vdW) forces between two adjacent tubes. Lennard-Jones potential is used to calculate the vdW ...

The theory and first implementation of a vibrational coupled cluster (VCC) method for calculations of the vibrational structure of molecules is presented. Different methods for introducing approximate VCC methods are discussed including truncation according to a maximum number of simultaneous mode excitations as well as an interaction space order concept is introduced. The theory is tested on c...

We demonstrate vibrational climbing in the CO stretch of carboxyhemoglobin pumped by midinfrared chirped ultrashort pulses. By use of spectrally resolved pump-probe measurements, we directly observed the induced absorption lines caused by excited vibrational populations up to v = 6. In some cases, we also observed stimulated emission, providing direct evidence of vibrational population inversio...

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...