Ab initio calculation of the KRb dipole moments

The relativistic configuration interaction valence bond method has been used to calculate permanent and transition electric dipole moments of the KRb heteronuclear molecule as a function of internuclear separation. The permanent dipole moment of the ground state $X^1\Sigma^+$ potential is found to be 0.30(2) $ea_0$ at the equilibrium internuclear separation with excess negative charge on the potassium atom. For the $a^3\Sigma^+$ potential the dipole moment is an order of magnitude smaller (1 $ea_0=8.47835 10^{-30}$ Cm) In addition, we calculate transition dipole moments between the two ground-state and excited-state potentials that dissociate to the K(4s)+Rb(5p) limits. Using this data we propose a way to produce singlet $X^1\Sigma^+$ KRb molecules by a two-photon Raman process starting from an ultracold mixture of doubly spin-polarized ground state K and Rb atoms. This Raman process is only allowed due to relativistic spin-orbit couplings and the absence of gerade/ungerade selection rules in heteronuclear dimers.Comment: 16 pages, 7 figure

HIGH ROVIBATIONAL LEVELS IN THE A1Σu+A^{1}\Sigma_{u}^{+} AND F1Σg+F^{1}\Sigma_{g}^{+} STATES OF 7Li2^{7}Li_{2}

Author Institution: Physics Department, Temple University; Physics Department, Dalian Institute of Chemical physicsHigh rovibrational levels in the $A \ {^{1}} \Sigma^{+}_{u}$ have been observed by cw triple resonance spectroscopy. Population was moved to the $F {^{1}}\Sigma^{+}_{g}$ state via $X \ {^{1}} \Sigma^{+}_{g} \rightarrow A \ {^{1}} \Sigma^{+}_{u} \rightarrow F \ {^{1}} \Sigma^{+}_{g}$ which employed two ring dye lasers. A Ti-Sapphire ring laser then dumped population back to higher levels in the $A \ {^{1}} \Sigma^{+}_{u}$ state. These levels were detected as dips in the collision induced side fluorescence, $2 {^{3}}\Pi_{g} \rightarrow a {^{3}} \Sigma^{+}_{u}$, which was monitored using a filtered PMT. High levels in the $F {^{1}}\Sigma^{+}_{g}$ state have been observed using optical double resonance (OODR). Rovibrational levels have been observed up to and beyond the shelf in this state using a filtered PMT and an ionization detector

ANALYSIS OF PERTURBATIONS OBSERVED IN THE FT SPECTRA OF CuCl2CuCl_{2}

Author Institution: Laboratoire de Spectrom\'etrie Ionique et Mol\'eculaire, CNRS et Universit\'e Lyott-I (UMR 5579), Campus la Doua; Physical and Theoretical Chemistry Laboratory, Oxford UniversityAbnormally large e-f separations have been observed in the $(v_{1},0,v_{3})$ levels of the ground $X^{2}\Pi_{g(3/2)}$, state of $CuCl_{2}$ about $2500\;cm^{-1}$ above the lowest vibrational level (0,0,0). The largest splitting are accompanied by extra lines in the dispersed fluorescence spectra. Some of the extra lines have resolvable Cu hyperfine structure; they are assigned as transitions to levels winch result from mixing essentially between $^{2}\Pi_{g(1/2)}$ and a nearby $^{2}\Sigma_{g}$ state. We have used an effective Hamiltonian to model the $^{2}\Pi \sim ^{2}\Sigma$ interaction and derived molecular constants for the unknown $^{2}\Sigma$ state using a non-linear least-squares fitting routine. Taking an arbitrary value of the spin-orbit parameter $A_{\Pi}$ of-$300\;cm^{-1}$, we estimate the $^{2}\Sigma$ state to lie around $3000\;cm^{-1}$ above the (0,0,0) level of the $X^{2}\Pi_{g(3/2)}$ ground state

TRULY TRANSFORM-LIMITED LASER PULSES FOR PRECISE MULTIPHOTON SPECTROSCOPY IN SMALL MOLECULES

$^{1}$N. Melikechi, S. Gangopadhyay, and E.E. Eyler, J. Opt. Soc. Am. B 11, 2402 (1994). $^{2}$J.M. Gilligan and E.E. Eyler, Phys. Rev. A 46, 3676 (1992); J.D. Meiners, M.S. thesis, University of Delwaware, 1994 (unpublished).Author Institution: University of Delaware, Newark, DE 19716.; Delaware State College, Dover, DE 19901.Ideally, pulse-amplified cw lasers combine the high peak powers of a nanosecond pulsed laser with the resolution and controllability of a continuous laser. In practice, optical phase perturbations in the amplifier chain can produce substantial chirping and shifting of the laser frequency, sometimes by $hundreds of MHz.^{1}$ Recently, our group has demonstrated that additional frequency shifts occur when optical harmonic generation is performed with imperfect phase matching. We describe recent efforts to understand the sources of both types of perturbations, and to reduce them by redesigning the optical system. The most significant improvement is accomplished by tailoring a laser dye mix that has an excited-state susceptibility near zero at the operating wavelength. Dramatic improvements have been obtained at wavelengths near 605 nm, required for our precise multiphoton measurements of transitions to the EF(2s\sigma) {^{1}{\Sigma^{+}}_{g} state in molecular hydrogen. Optical heterodyning is used to explicitly measure the time-dependent optical phase. The average frequency shift is now typically 1 MHz (previously it was about 20 MHz), and the chirp is constrained to a range of about 10 MHz (previously about 150 MHz). The result is a temporally smooth pulse, eight nanoseconds in duration, with a bandwidth very close to the theoretical transform limit. This has allowed us to overcome significant difficulties that were encountered in the final stages of data analysis of our previous measurements of two-photon $EF\leftarrow X$ intervals in $H_{2}$, HD, and ${D_{2}}^{2}$, so the accuracy now exceeds one part in $10^{g}$. The same techniques will find applications not only for other high-resolution measurements, but also for spectroscopic methods that use optical phase information, such as frequency-modulation spectroscopy in the far ultraviolet