We discuss the production of ultracold molecules in their electronic ground state by photoassociation employing electronically excited states with ion-pair character and strong spin-orbit interaction. A short photoassociation laser pulse drives a nonresonant three-photon transition for alkali-metal atoms colliding in their lowest triplet state. The excited-state wave packet is transferred to th...

Processes mediated by two virtual low-energy photons contribute quite significantly to the energy of hydrogenic S states. The corresponding level shift is of the order of (α/π) (Zα)6me c and may be ascribed to a two-loop generalization of the Bethe logarithm. For 1S and 2S states, the correction has recently been evaluated by Pachucki and Jentschura [Phys. Rev. Lett. 91, 113005 (2003)]. Here, w...

Resonantly-enhanced one-color two-photon ~111! ionization spectra of jet-cooled methylamines (CH3NH2 and CH3ND2) reveal the vibrational structures of these molecules in predissociative à states. Rotational fine structure is clearly resolved for CH3ND2 at the origin and first wagging vibrational level in the excited state. The spectral linewidth becomes homogeneously broadened to give only vibra...

We report calculations of the vibrational spectrum of HD2 in its first-excited electronic state by using a coordinate-transformation technique. The implications of the geometric phase (GP) effect in the spectrum have been investigated. The results show that the lowest 45 vibrational levels calculated using the traditional Longuet-Higgins phase (φ/2, where φ is the pseudorotation angle) are in g...

UV-photoelectrons of mass-defined indium and thallium cluster anions have been analyzed at a detachment energy of 3.68eV in the size range n = 2-20. The photoelectron threshold energies are in rough agreement with the values predicted by the metal droplet model. A number of low-lying excited states of the neutral-clusters are detected. The high atomic s-orbital binding energies appear to induce...

The rotationally resolved spectrum of the @ band of the S, + So electronic transition of the benzene-N, van der Waals complex has been recorded and 119 transitions assigned. The G,H,.N, complex, produced in a pulsed molecular beam, was detected by mass-selected two-photon twecolour ionization employing a high-resolution (Av uv= 100 MHz, fwhm) pulsed-amplified cw laser for the resonant intermedi...

Photoacoustic detection has b~en used to monitor a stimulated emission pumping process in p-difluorobenzene. Using the A B 2u 5 1 state as an intermediate, several vibrational levels of the ground electronic state were populated. The photoacoustic method is an attractive alternative to other detection techniques because of its sensitivity, simplicity, and its ability to differentiate between st...

Luminescence spectra of organometallic molecules in crystals or glasses are discussed and interpreted by using the time-dependent Ž . theory of electronic spectroscopy. Emphasis is placed on determining bond length and bond angle changes excited-state distortions between the ground and excited electronic states. The physical meaning of the dynamic processes and the molecular properties are desc...

We propose an effective method for the detection and identification of dangerous substances by using the broadband THz pulse. This pulse excites, for example, many vibrational or rotational energy levels of molecules simultaneously. By analyzing the time-dependent spectrum of the THz pulse transmitted through or reflected from a substance, we follow the average response spectrum dynamics. Compa...

Molecules are made up of atoms, which are composed of a positively charged nucleus and negatively charged electrons orbiting it at various energy levels. Light is composed of individual packets of energy, called photons. Electrons can jump from one orbit to another by either, absorbing energy and moving to a higher level (excited state), or emitting energy and transitioning to a lower level. Su...