Franck–Condon simulations of transition-state spectra for the OH + H2O and OD + D2O reactions

Quantum wave packet calculations in reduced dimensions were performed to analyze the experimentally measured transition-state spectra of the OH + H2O and OD + D2O hydrogen exchange reactions.

Astrophysical detections and databases for the mono deuterated species of acetaldehyde CH2DCOH and CH3COD

Context. Detection of deuterated species may provide information on the evolving chemistry in the earliest phases of star-forming regions. For molecules with two isomeric forms of the same isotopic variant, gas-phase and solid-state formation pathways can be differentiated using their abundance ratio. Aims. Spectroscopic databases for astrophysical purposes are built for the two mono deuterated isomeric species CH2DCOH and CH3COD of the complex organic molecule acetaldehyde. These databases can be used to search and detect these two species in astrophysical surveys, retrieving their column density and therefore abundances. Methods. Submillimeter wave and terahertz transitions were measured for mono deuterated acetaldehyde CH2DCOH which is a non-rigid species displaying internal rotation of its asymmetrical CH2D methyl group. An analysis of a dataset consisting of previously measured microwave data and the newly measured transition was carried out with a model accounting for the large amplitude torsion. Results. The frequencies of 2556 transitions are reproduced with a unitless standard deviation of 2.3 yielding various spectroscopic constants. Spectroscopic databases for astrophysical purposes were built for CH2DCOH using the results of the present analysis and for CH3COD using the results of a previous spectroscopic investigation. These two species were both searched for and are detected toward a low-mass star-forming region. Conclusions. We report the first detection of CH2DCOH (93 transitions) and the detection of CH3COD (43 transitions) species in source B of the IRAS 16293−2422 young stellar binary system located in the ρ Ophiuchus cloud region, using the publicly available ALMA Protostellar Interferometric Line Survey.

Effects of ultra-light dark matter on the gravitational quantum well

We study the influence of a periodic perturbation of the effective masses of fermions, due to the assumed semiclassical ultra-light dark matter (ULDM) background, on the motion of neutrons in a gravitational quantum well (GQW). Our focus is on the transition probability between the lowest two energy states, with the Rabi frequency in the kHz region corresponding to the series of “sweet spot” DM masses in the [Formula: see text][Formula: see text]eV ballpark. The relevant probability is written in terms of the specific mass and of the effective coupling to the ordinary matter. These parameters can be constrained by the nonobservation of any significant deviations of the measured transition probabilities from the DM-free picture.

High-resolution spectroscopy of K-shell praseodymium with a high-energy microcalorimeter

We present a measurement of the K-shell spectrum of He-like through Be-like praseodymium ions trapped in the Livermore SuperEBIT electron beam ion trap using a bismuth absorber pixel on the XRS/EBIT microcalorimeter. This measurement is the first of its kind where the n = 2 to n = 1 transitions of the various charge states are spectroscopically resolved. The measured transition energies are compared with theoretical calculations from several atomic codes.PACS Nos.: 32.30.–r, 32.30.Rj, 39.30.+w

Reanalysis of the Nuclear Quadrupole Coupling in the Rotational Spectrum of N-Methylpyrrole

The rotational spectrum of N-methylpyrrole has been measured with pulsed nozzle Fourier transform microwave spectrometers between 6 and 38 GHz. The quadrupole hyperfine structure due to 14N has been reanalyzed in the A (m = 0) state o f the methyl internal rotation. Improved rotational constants, centrifugal distortion constants, and quadrupole coupling constants have been simultaneously determined from the measured transition frequencies in an iterative least-squares fit.

SABSA: SWITCHING-ACTIVITY-BASED STATE ASSIGNMENT

Many algorithms have been proposed for the state assignment of Finite-State Machines. The usual goal of these algorithms is to reduce the area required to implement these machines. This paper discusses SABSA, an algorithm whose goal is to reduce the number of state bit transitions in the operating environment. SABSA does this by considering measured transition probabilities between states. When combined with a technology such as CMOS, this leads to lower power consumption. A RISC controller was taken from high level design to transistor level layout, and a power reduction of 35% was obtained with this new state assignment algorithm.