STIRAP (Stimulated Raman Adiabatic Passage) is a powerful laser-based method, usually involving two photons, for efficient and selective transfer of population between quantum states. A particularly interesting feature is the fact that the coupling between the initial and the final quantum states is via an intermediate state even though the lifetime of the latter can be much shorter than the interaction time with the laser radiation. Nevertheless, spontaneous emission from the intermediate state is prevented by quantum interference. Maintaining the coherence between the initial and final state throughout the transfer process is crucial.STIRAP was initially developed with applications in chemical dynamics in mind. That is why the original paper of 1990 was published in The Journal of Chemical Physics. However, as of about the year 2000, the unique capabilities of STIRAP and its robustness with respect to small variations of some experimental parameters stimulated many researchers to apply the scheme in a variety of other fields of physics. The successes of these efforts are documented in this collection of articles. In Part A the experimental success of STIRAP in manipulating or controlling molecules, photons, ions or even quantum systems in a solid-state environment is documented. After a brief introduction to the basic physics of STIRAP, the central role of the method in the formation of ultra-cold molecules is discussed, followed by a presentation of how precision experiments (measurement of the upper limit of the electric dipole moment of the electron or detecting the consequences of parity violation in chiral molecules) or chemical dynamics studies at ultra-low temperatures benefit from STIRAP. Next comes the STIRAP-based control of photons in cavities followed by a group of three contributions which highlight the potential of the STIRAP concept in classical physics by presenting data on the transfer of waves (photonic, magnonic and phononic) between respective wave guides. The works on ions or ion-strings discuss options for applications e.g. in quantum information. Finally, the success of STIRAP in the controlled manipulation of quantum states in solid-state systems, which are usually hostile towards coherent processes, is presented, dealing with data storage in rare-earth ion doped crystals and in NV-centers or even in superconducting quantum circuits. The works on ions and those involving solid-state systems emphasize the relevance of the results for quantum information protocols.Part B deals with theoretical work including further concepts relevant for quantum information or invoking STIRAP for the manipulation of matter waves. The subsequent articles discuss experiments underway to demonstrate the potential of STIRAP for populating otherwise inaccessible high-lying Rydberg states of molecules, or controlling and cooling the translational motion of particles in a molecular beam or the polarization of angular momentum states. The series of articles concludes with a more speculative application of STIRAP i...

We have set up an experiment for the efficient population transfer by a sequential two photon-absorption and stimulated emission-process in a molecular beam to prepare quantum states of well defined parity and their subsequent sensitive detection. This provides a proof of principle for an experiment which would allow for parity selection and measurement of the time evolution of parity in chiral molecules, resulting in a measurement of the parity violating energy difference ΔpvE between enantiomers of chiral molecules. Here, we present first results on a simple achiral molecule demonstrating efficient population transfer (about 80% on the average for each step) and unperturbed persistence of a selected excited parity level over flight times of about 1.3 ms in the beam. In agreement with model calculations with and without including nuclear hyperfine structure, efficient population transfer can be achieved by a rather simple implementation of the rapid adiabatic passage method of Reuss and coworkers and considering also the stimulated Raman adiabatic passage technique of Bergmann and coworkers as an alternative. The preparation step uses two powerful single mode continuous wave optical parametric oscillators of high frequency stability and accuracy. The detection uses a sensitive resonantly enhanced multiphoton ionization method after free flight lengths of up to 0.8 m in the molecular beam. Using this technique, we were able to also resolve the nuclear hyperfine structure in the rovibrational levels of the ν1 and ν3 fundamentals as well as the 2ν4 overtone of (14)NH3, for which no previous data with hyperfine resolution were available. We present our new results on the quadrupole coupling constants for the ν1, ν3, and 2ν4 levels in the context of previously known data for ν2 and its overtone, as well as ν4, and the ground state. Thus, now, (14)N quadrupole coupling constants for all fundamentals and some overtones of (14)NH3 are known and can be used for further theoretical analysis.

COMMUNICATIONSwith a normal focus molybdenum-target X-ray tube operated at 2.0 kW (50 kV. 40 mA) 191. A total of 1321 frames ofdata were collected using a narrow-frame method with scan widths of 0.3' in w and exposure times of 30 sec per frame using a crystal-to-detector distance of 6.015 cm (maximum 211 angle 51.62"). The total data collection time was approximately 13 h. Frames were integrated with the Siemens SAINT program to yield a total of 14059 reflections, of which 2213 were independent (R,,, = 0.0307, Laue symmetry hlmmm, R,,, = 0.01 79) and 1993 were above 4u(F). The unit cell parameters (at 153 K) of u = h = 16.5617(2), c = 15.4433(2) A were based upon least-squares refinement of the three-dimensional centroids of 8192 reflections. The cell volume and density were 3668 A' and 1.547 gcm-3, respectwely. By assuming a merohedrally twinned trigonal specimen, twinning law (0 -1 0 -1 0 0 0 0 -1) and space group P%l, Ru of position A is found at (1/3,2/3. z) (site simmetry C35)

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Previous experimental and theoretical results on the strength of the important fine structure transition in the Iodine atom scatter over a very wide range, indicating great uncertainty. We have therefore carried out new theoretical calculations and experiments to reinvestigate the transition probability between the fine structure levels 2P3/2 and 2P1/2 in the electronic ground configuration of atomic iodine. In the experiments a tunable, narrow band width, near‐IR laser was used to measure the iodine absorption spectrum with sub‐Doppler resolution. The I‐atoms in the 2P3/2 ground state are produced either in a I2 = 2I equilibriums at elevated temperatures or from IR‐multiphoton dissociation of CF3I, CF3CHFI or C6F5I. The two different experimental methods to produce I‐atoms in the ground state allow for a careful check on possible systematic errors. In the experiments an integrated absorption cross section of Gexp = ∫ σ(v) dln v = (1050±250) fm2 was determined, corresponding to a radiative lifetime of 140 ms for spontaneous emission from the upper level. We have in addition carried out nonrelativistic MCHF calculations and relativistic Dirac‐Fock calculations on this transition. The results of the MCHF calculations (1200 fm2) agree well with experiment and a crude estimate from a simple LS coupling model.