3,474 research outputs found
[Review of] Carol Bruchac, Linda Hogan, Judith McDaniel, eds. The Stories We Hold Secret-Tales of Women\u27s Spiritual Development
The Stories We Hold Secret -- Tales of Women\u27s Spiritual Development is an anthology of thirty-one short fiction pieces written by and about women in America. These are not stories about extraterrestrial visits, enlightenment through gurus, or dramatic religious conversion; rather, these are stories of inner knowing, of our holy dailiness, as Linda Hogan says in the preface. The stories are as varied as women\u27s experience, from the quietness of a Native American woman cooking beans and cornbread in her kitchen to the tumult of a woman who for the first time becomes involved with a workers\u27 strike
A simple approach to the correlation of rotovibrational states in four-atomic molecules
The problem of correlation between quantum states of four-atomic molecules in
different geometrical configurations is reviewed in detail. A general, still
simple rule is obtained which allows one to correlate states of a linear
four-atomic molecule with those of any kind of non-linear four-atomic molecule.Comment: 16 pages (+8 figures), Postscript (ready to print!
Optimal Topological Test for Degeneracies of Real Hamiltonians
We consider adiabatic transport of eigenstates of real Hamiltonians around
loops in parameter space. It is demonstrated that loops that map to nontrivial
loops in the space of eigenbases must encircle degeneracies. Examples from
Jahn-Teller theory are presented to illustrate the test. We show furthermore
that the proposed test is optimal.Comment: Minor corrections, accepted in Phys. Rev. Let
CO oxidation at Pd(100): A first-principles constrained thermodynamics study
The possible formation of oxides or thin oxide films (surface oxides) on late
transition metal surfaces is recently being recognized as an essential
ingredient when aiming to understand catalytic oxidation reactions under
technologically relevant gas phase conditions. Using the CO oxidation at
Pd(100) as example, we investigate the composition and structure of this model
catalyst surface over a wide range of (T,p)-conditions within a multiscale
modeling approach where density-functional theory is linked to thermodynamics.
The results show that under the catalytically most relevant gas phase
conditions a thin surface oxide is the most stable "phase" and that the system
is actually very close to a transition between this oxidic state and a reduced
state in form of a CO covered Pd(100) surface.Comment: 13 pages including 7 figures; related publications can be found at
http://www.fhi-berlin.mpg.de/th/th.htm
Predicting and verifying transition strengths from weakly bound molecules
We investigated transition strengths from ultracold weakly bound 41K87Rb
molecules produced via the photoassociation of laser-cooled atoms. An accurate
potential energy curve of the excited state (3)1Sigma+ was constructed by
carrying out direct potential fit analysis of rotational spectra obtained via
depletion spectroscopy. Vibrational energies and rotational constants extracted
from the depletion spectra of v'=41-50 levels were combined with the results of
the previous spectroscopic study, and they were used for modifying an ab initio
potential. An accuracy of 0.14% in vibrational level spacing and 0.3% in
rotational constants was sufficient to predict the large observed variation in
transition strengths among the vibrational levels. Our results show that
transition strengths from weakly bound molecules are a good measure of the
accuracy of an excited state potential.Comment: 7 pages, 7 figure
On the Prospects for Laser Cooling of TlF
We measure the upper state lifetime and two ratios of vibrational branching
fractions f_{v'v} on the B^{3}\Pi_{1}(v') - X^{1}\Sigma^{+}(v) transition of
TlF. We find the B state lifetime to be 99(9) ns. We also determine that the
off-diagonal vibrational decays are highly suppressed: f_{01}/f_{00} <
2x10^{-4} and f_{02}/f_{00} = 1.10(6)%, in excellent agreement with their
predicted values of f_{01}/f_{00} < 8x10^{-4} and f_{02}/f_{00} = 1.0(2)% based
on Franck-Condon factors calculated using Morse and RKR potentials. The
implications of these results for the possible laser cooling of TlF and
fundamental symmetries experiments are discussed.Comment: 5 pages, 2 figure
Molecular Dipolar Crystals as High Fidelity Quantum Memory for Hybrid Quantum Computing
We study collective excitations of rotational and spin states of an ensemble
of polar molecules, which are prepared in a dipolar crystalline phase, as a
candidate for a high fidelity quantum memory. While dipolar crystals are formed
in the high density limit of cold clouds of polar molecules under 1D and 2D
trapping conditions, the crystalline structure protects the molecular qubits
from detrimental effects of short range collisions. We calculate the lifetime
of the quantum memory by identifying the dominant decoherence mechanisms, and
estimate their effects on gate operations, when a molecular ensemble qubit is
transferred to a superconducting strip line cavity (circuit QED). In the case
rotational excitations coupled by dipole-dipole interactions we identify
phonons as the main limitation of the life time of qubits. We study specific
setups and conditions, where the coupling to the phonon modes is minimized.
Detailed results are presented for a 1D dipolar chain
Strong field ionization to multiple electronic states in water
High harmonic spectra show that laser-induced strong field ionization of
water has a significant contribution from an inner-valence orbital. Our
experiment uses the ratio of H2O and D2O high harmonic yields to isolate the
characteristic nuclear motion of the molecular ionic states. The nuclear motion
initiated via ionization of the highest occupied molecular orbital (HOMO) is
small and is expected to lead to similar harmonic yields for the two isotopes.
In contrast, ionization of the second least bound orbital (HOMO-1) exhibits
itself via a strong bending motion which creates a significant isotope effect.
We elaborate on this interpretation by simulating strong field ionization and
high harmonic generation from the water isotopes using the time-dependent
Schr\"odinger equation. We expect that this isotope marking scheme for probing
excited ionic states in strong field processes can be generalized to other
molecules
A Spectroscopic Survey of Electronic Transitions of CH, CH, and CD
Electronic spectra of CH are measured in the cm
domain using cavity ring-down spectroscopy of a supersonically expanding
hydrocarbon plasma. In total, 19 (sub)bands of CH are presented, all
probing the vibrational manifold of the B electronically excited state.
The assignments are guided by electronic spectra available from matrix
isolation work, isotopic substitution experiments (yielding also spectra for
CH and CD), predictions from ab initio calculations as well as
rotational fitting and vibrational contour simulations using the available
ground state parameters as obtained from microwave experiments. Besides the
origin band, three non-degenerate stretching vibrations along the
linear backbone of the CH molecule are assigned: the mode
associated with the C-C bond vibration and the and modes
associated with CC triple bonds. For the two lowest and
bending modes, a Renner-Teller analysis is performed identifying the
() and both () and
() components. In addition, two higher lying bending
modes are observed, which are tentatively assigned as ()
and () levels. In the excitation region below the first
non-degenerate vibration (), some transitions are
observed that are assigned as even combination modes of low-lying bending
vibrations. The same holds for a transition found above the
level. From these spectroscopic data and the vibronic analysis a
comprehensive energy level diagram for the B state of CH is derived
and presented.Comment: Accepted for publication in The Journal of Physical Chemistry A (26
July 2016
- …