Mechanisms and rates of relaxation of optically excited states are important in the study of almost every material. They often determine the efficiency of some desired photoeffect and usually carry interesting information about the excited states themselves. Many fluorescent systems have been analyzed on the basis of the "universal relationship" introduced by Kennard and by Stepanov (K-S). Thes...

Fluorescence resonance energy transfer represents a mechanism to transport light energy at the nano-scale as is exemplified by nature’s light harvesting complexes. Here we used DNA origami to arrange fluorophores that transport excited state energy from an input dye to an output dye. We demonstrate that energy transfer paths can be controlled on the single-molecule level by the presence of a “j...

Photoionization of Li-like argon, ðhnþAr XVI-Ar XVIIþeÞ, and He-like argon, ðhnþ Ar XVII-Ar XVIIIþeÞ, are studied using the relativistic Breit–Pauli R-matrix (BPRM) method. Results include both the partial and total photoionization cross-sections of fine structure levels with 1=2r Jr17=2, nr10 and 0r lr9 of Ar XVI and with 0r Jr10, nr10 and 0r lr9 of Ar XVII. They correspond to 98 bound levels ...

We present high-level ab initio calculations for the global adiabatic potential energy surfaces of the ground state (X̃ A8) and several excited states ~Ã A8, B̃ A9, C̃ A8, D̃ A8, and Ẽ A9! of LiFH, including the valleys leading to Li1HF and LiF1H. The ab initio calculations were carried out using the multireference singles and doubles configuration interaction method with 99 reference configuration...

We have observed the coherent exchange of a single energy quantum between a flux qubit and a superconducting LC circuit acting as a quantum harmonic oscillator. The exchange of an energy quantum is known as the vacuum Rabi oscillation: the qubit is oscillating between the excited state and the ground state and the oscillator between the vacuum state and the first excited state. We also show tha...

Atoms of each element in the ground state have a specific electron configuration. These atoms can absorb quanta of light energy when that energy exactly matches the energy associated with any of the allowed electronic transitions within that atom. (See Figure 1.) Atoms that absorb energy are said to be in an excited state. Their electrons absorb exact quanta of energy, elevate to higher energy ...

Raman scattering is widely used to study the vibrational and rotational properties of molecules. Normally infrared spectroscopy is needed to probe these levels but because of the Raman effect it is possible to excite these levels using visible light. In some cases Raman scattering is the only way to study these transitions. An example of this is the molecule H2. Since this molecule has no elect...

Three pulse photon echo peak shift spectroscopy and transient grating measurements on Zn-substituted cytochrome c, Zn-tetraphenylporphyrin, and Zn-protoporphyrin IX are reported. The effects of protein conformation, axial ligation, and solvent are investigated. Numerical simulations of the peak shift and transient grating experiments are presented. The simulations employed recently derived opti...