647 research outputs found
QED effects in molecules: test on rotational quantum states of H
Quantum electrodynamic effects have been systematically tested in the
progression of rotational quantum states in the
vibronic ground state of molecular hydrogen. High-precision Doppler-free
spectroscopy of the (0,0) band
was performed with 0.005 cm accuracy on rotationally-hot H (with
rotational quantum states J up to 16). QED and relativistic contributions to
rotational level energies as high as 0.13 cm are extracted, and are in
perfect agreement with recent calculations of QED and high-order relativistic
effects for the H ground state.Comment: 4 pages, 3 figures, to be published in Physical Review Letter
The lady vanishes: what's missing from the stem cell debate
Most opponents of somatic cell nuclear transfer and embryonic stem cell technologies base their arguments on the twin assertions that the embryo is either a human being or a potential human being, and that it is wrong to destroy a human being or potential human being in order to produce stem cell lines. Proponentsâ justifications of stem cell research are more varied, but not enough to escape the charge of obsession with the status of the embryo. What unites the two warring sides in âthe stem cell warsâ is that women are equally invisible to both: âthe lady vanishesâ. Yet the only legitimate property in the body is that which women possess in their reproductive tissue and the products of their reproductive labour. By drawing on the accepted characterisation in law of property as a bundle of rights, and on a Hegelian model of contract as mutual recognition, we can lessen the impact of the tendency to regard women and their eggs as merely receptacles and womenâs reproductive labour as unimportant
Achieving diffraction-limited performance on the Berkeley MET5
The Berkeley MET5, funded by EUREKA, is a 0.5-NA EUV projection lithography tool located at the Advanced Light Source at Berkeley National Lab. Wavefront measurements of the MET5 optic have been performed using a custom in-situ lateral shearing interferometer suitable for high-NA interferometry. In this paper, we report on the most recent characterization of the MET5 optic demonstrating an RMS wavefront 0.31 nm, and discuss the specialized mask patterns, gratings, and illumination geometries that were employed to accommodate the many challenges associated with high-NA EUV interferometry
High-resolution Fourier-transform XUV photoabsorption spectroscopy of 14N15N
The first comprehensive high-resolution photoabsorption spectrum of 14N15N
has been recorded using the Fourier-transform spectrometer attached to the
Desirs beamline at the Soleil synchrotron. Observations are made in the extreme
ultraviolet (XUV) and span 100,000-109,000 cm-1 (100-91.7 nm). The observed
absorption lines have been assigned to 25 bands and reduced to a set of
transition energies, f values, and linewidths. This analysis has verified the
predictions of a theoretical model of N2 that simulates its photoabsorption and
photodissociation cross section by solution of an isotopomer independent
formulation of the coupled-channel Schroedinger equation. The mass dependence
of predissociation linewidths and oscillator strengths is clearly evident and
many local perturbations of transition energies, strengths, and widths within
individual rotational series have been observed.Comment: 14 pages, 8 figures, one data archiv
Accurate laboratory wavelengths of the e 3 ÎŁâ(ν' = 5) â X 1 ÎŁ+(ν'' = 0) band of 12C16O
CITATION: Dickenson, G. D. et al. 2010. Accurate laboratory wavelengths of the e 3 ÎŁâ(ν' = 5) â X 1 ÎŁ+(ν'' = 0) band of 12C16O. Astrophysical Journal Letters, 714(2):L268âL270, doi:10.1088/2041-8205/714/2/L268.The original publication is available at https://iopscience.iop.org/journal/2041-8205The forbidden singlet-triplet transitions of carbon monoxide (CO) are important in the interpretation of vacuum ultraviolet interstellar absorption spectra and in particular for the measurement of large CO column densities. Twenty rovibronic lines of the e 3ÎŁâ(ν' = 5) â X 1ÎŁ+(ν'' = 0) band of 12 C 16O for which laboratory wavelengths were previously unavailable were identified in laser-induced fluorescence excitation spectra. Wavelengths were assigned to five rovibronic transitions to an average accuracy of 0.0028 Ă
. A further 15 lines could not be fully resolved and average wavelengths were measured for these groups of closely spaced lines. A wavelength difference of 0.011 Âą 0.0028 Ă
between the measured wavelengths and the calculated wavelengths in the atlas of Eidelsberg & Rostas demonstrates the need for more experimental data on CO.https://iopscience.iop.org/article/10.1088/2041-8205/714/2/L268Publisher's versio
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