Search results for "Fourier transform"
showing 10 items of 1138 documents
Hyperfine structure measurements of neutral niobium with Fourier transform spectroscopy
2010
Aims. We report on experimental studies of hyperfine structure splitting of neutral niobium.Methods. We used high-resolution Fourier transform spectroscopy to record a spectrum of niobium produced with a hollow cathode discharge lamp in the range of wavenumbers from 10 000 cm-1 to 30 000 cm-1 .Results. The magnetic dipole hyperfine structure constants A were determined for the 109 levels of odd parity by analyzing the profiles of 224 spectral lines. The A values of 57 of these level are reported for the first time.
Influence of gravity vector on eye movement elicited by linear acceleration.
1991
When the body/head motion is sensed by otolith organs, they respond not only to the resultant acceleration of the motion but also to the gravitational force. We investigated the influence of the gravity vector on the otolithic-ocular reflex caused by motion in normal subjects. The sled type linear accelerator, moving back and forth with a frequency of 0.25 Hz and an amplitude of 2 m, generated right-left linear acceleration with a maximum magnitude of 0.5 g. We tested every subject under seven different postures: 1) 135 degrees forward tilted (F.T.), 2) 90 degrees F.T., 3) 45 degrees F.T., 4) upright sitting, 5) 45 degrees backward tilted (B.T.), 6) 90 degrees B.T., and 7) 135 degrees B.T. …
HIGH-RESOLUTION FOURIER TRANSFORM SPECTROSCOPY OF LANTHANUM IN Ar DISCHARGE IN THE NEAR-INFRARED
2013
A high-resolution spectrum of lanthanum has been recorded by a Fourier Transform spectrometer in the wavelength range from 833 nm to 1666 nm (6000 cm{sup –1} to 12,000 cm{sup –1}) using as light source a hollow cathode lamp operated with argon as the discharge carrier gas. In total, 2386 spectral lines were detected in this region, of which 555 lines could be classified as La I transitions and 10 lines as La II transitions. All La II transitions and 534 of these La I transitions were classified for the first time, and 6 of the La II transitions and 433 of the classified La I transitions appear to be new lines, which could not be found in the literature. The corresponding energy level data o…
Arbitrary qudit gates by adiabatic passage
2013
We derive an adiabatic technique that implements the most general SU($d$) transformation in a quantum system of $d$ degenerate states, featuring a qudit. This technique is based on the factorization of the SU($d$) transformation into $d$ generalized quantum Householder reflections, each of which is implemented by a two-shot stimulated Raman adiabatic passage with appropriate static phases. The energy of the lasers needed to synthesize a single Householder reflection is shown to be remarkably constant as a function of $d$. This technique is directly applicable to a linear trapped ion system with $d+1$ ions. We implement the quantum Fourier transform numerically in a qudit with $d=4$ (defined…
The hot bands of silane between 2120 and 2270cm−1
2005
Abstract The infrared spectrum of the SiH 4 molecule has been recorded between 2040 and 2320 cm −1 using the high-resolution Fourier interferometer of the Laboratoire de Photophysique Moleculaire ( Orsay , France ). The resolution was 5.4 × 10 −3 cm −1 . In this region, many lines were previously analyzed and assigned to the ν 1 / ν 3 stretching dyad of 28 SiH 4 , 29 SiH 4 , and 30 SiH 4 molecules [J. Mol. Spectrosc. 143 (1990) 35]. However, several lines in the spectrum were not assigned. The results obtained in our previous study [J. Mol. Spectrosc. 197 (1999) 307] of the infrared spectrum of 28 SiH 4 , in the bending-stretching tetrad region at 3100 cm −1 , enabled us to assign 204 of t…
Analysis of the Infrared Fourier Transform Spectrum of the Spectra of Silane in the Range 2930-3300 cm(-1).
1999
The infrared spectrum of (28)SiH(4) between 2930 and 3300 cm(-1) was recorded using the Laboratoire de Physique Moleculaire et Applications (LPMA.) Fourier transform spectrometer. The instrumental response function width chosen makes it possible to obtain a Doppler-limited spectrum. The observed spectrum belongs to the tetrad built with one quantum of stretching mode (nu(1) or nu(3)) and one quantum of bending mode (nu(2) or nu(4)). The excited states are formed from eight vibrational sublevels: nu(1) + nu(2)(E), nu(1) + nu(4)(F(2)), nu(2) + nu(3)(F(1) + F(2)), and nu(3) + nu(4)(A(1) + E + F(1) + F(2)). The intricacy of the upper states was resolved using the variations of the line strength…
High-Resolution Spectroscopy and Preliminary Analysis of the ν1/ν8 Dyad of SF535Cl
2001
Abstract The Fourier transform infrared spectrum of monoisotopic SF 5 35 Cl has been recorded in the 650- to 960-cm −1 region at a temperature of 203 K, a pressure of 0.2 mbar, and an instrumental bandwidth of 0.002 cm −1 . The ν 1 /ν 8 dyad near 900 cm −1 has been analyzed with an effective Hamiltonian developed up to the fourth order and the help of a recently developed set of programs called C 4 v TDS ( C 4 v Top Data System, http://www.u-bourgogne.fr/LPUB/C4VTDS.html ); 1346 transitions for ν 1 , 351 transitions for ν 8 , and 406 ground state combination differences have been assigned and fitted. A global fit has been obtained with an rms of 0.00082 cm −1 for the ν 1 ( a 1 ) band, of 0.…
Analysis of the infrared Fourier transform spectrum of the Dyad of 116SnH4
1990
Abstract The FTIR spectrum of monoisotopic 116SnH4 has been recorded with the Bruker 120 HR interferometer at Giessen, West Germany, in the ν 2 ν 4 range extending from 600 to 850 cm−1. The resolution (FWHM) was 2.1 × 10−3 cm−1. The Dyad ν 2 ν 4 (0100, 0001) was analyzed using a sixth-order Hamiltonian. The analysis of infrared transitions enabled us to determine 10 ground state parameters, 9 ν2 parameters, 17 ν4 parameters, and 18 interaction parameters. Of 3800 calculated transitions assigned to observed lines, 1183 unblended lines have been selected for the data refinement. For J ≤ 19, the value of the standard deviation is of the order of magnitude of the estimated experimental accuracy…
Oscillations of ECR ion source beam current along the beam transport of the JYFL K-130 cyclotron
2013
A versatile measurement system has been developed to study the temporal characteristics of ion beams in millisecond time scale. The system is composed of data acquisition hardware and LabVIEW based measurement and analysis program. The measurement system and ion beam current oscillation results measured with a 14 GHz AECR-U type ion source at University of Jyv"askyl"a, Department of Physics (JYFL), are presented. It is shown that the ion beams exhibit periodic current fluctuations at frequencies from 100 Hz to 1.5 kHz with amplitudes ranging from 1 to 65 percent of the average beam current. It is argued that these oscillations originate from the ion source plasma since their characteristics…
Energy and time-lag spectra of galactic black-hole X-ray sources in the low/hard state
2003
Most, probably all, accreting binaries that are believed to contain a black-hole emit radio waves when they are in the low/hard state. Whenever this radio emission has been resolved, a jet-like structure has become apparent. We propose that Compton upscattering of low-energy photons in the jet can explain both the energy spectra and the time lags versus Fourier frequency observed in the low/hard state of black-hole systems. The soft photons originate in the inner part of the accretion disk. We have performed Monte Carlo simulations of Compton upscattering in a jet and have found that for a rather wide range of values of the parameters we can obtain power-law high-energy X-ray spectra with p…