Wavelength standard at 543 nm and the corresponding ^127I_2 hyperfine transitions

2001 ◽  
Vol 18 (3) ◽  
pp. 363 ◽  
Author(s):  
Wang-Yau Cheng ◽  
Jow-Tsong Shy
Keyword(s):  
Hyperfine Transitions ◽  
Wavelength Standard

scholarly journals Precise Measurements of CH Maser Emission and Its Abundance in Translucent Clouds

2021 ◽  
Vol 257 (2) ◽  
pp. 47
Author(s):  
Ningyu Tang ◽  
Di Li ◽  
Gan Luo ◽  
Carl Heiles ◽  
Sheng-Li Qin ◽  
...  
Keyword(s):  
Thermal Equilibrium ◽  
Column Density ◽  
High Sensitivity ◽  
Local Thermal Equilibrium ◽  
Molecular Gas ◽  
Excitation Temperature ◽  
Hyperfine Transitions ◽  
Visible Wavelengths ◽  
Log Normal ◽  
Log Normal Distribution

Abstract We present high-sensitivity CH 9 cm ON/OFF observations toward 18 extragalactic continuum sources that have been detected with OH 18 cm absorption in the Millennium survey with the Arecibo telescope. CH emission was detected toward 6 of the 18 sources. The excitation temperature of CH has been derived directly through analyzing all detected ON and OFF velocity components. The excitation temperature of CH 3335 MHz transition ranges from −54.5 to −0.4 K and roughly follows a log-normal distribution peaking within [−5, 0] K, which implies overestimation by 20% to more than 10 times during calculating CH column density by assuming the conventional value of −60 or −10 K. Furthermore, the column density of CH would be underestimated by a factor of 1.32 ± 0.03 when adopting local thermal equilibrium assumption instead of using the CH three hyperfine transitions. We found a correlation between the column density of CH and OH following log N(CH) = (1.80 ± 0.49) and log N(OH −11.59 ± 6.87. The linear correlation between the column density of CH and H2 is consistent with that derived from visible wavelengths studies, confirming that CH is one of the best tracers of H2 components in diffuse molecular gas.

scholarly journals Ellipsometric spectroscopy of rubidium vapor cell at near-normal incidence

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
M. Mosleh ◽  
M. Ranjbaran ◽  
S. M. Hamidi ◽  
M. M. Tehranchi
Keyword(s):  
Normal Incidence ◽  
Metal Vapor ◽  
Dipole Interaction ◽  
Transition Line ◽  
Rubidium Vapor ◽  
Vapor Cell ◽  
Atomic Vapors ◽  
Hyperfine Transitions ◽  
Reflected Light ◽  
Medium Change

Abstract Various efforts have been made to overcome Doppler broadening in hyperfine measurement limitations in the atomic vapors spectroscopy and associated applications. The present study measured and calculated hyperfine resolved ellipsometric parameters through the near-normal reflectance spectra of the rubidium vapor cell in two experimental setups based on continuous and modulated pathway. The results indicated that valuable information could be extracted from the ellipsometric parameters about the atomic medium. Change in the ellipsometric parameters in each transition line confirms the existence of the elliptical polarization of the reflected light when it is exposed to the alkali metal vapor. Our results show that the ellipticity at 5S1/2 (Fg = 1, 2) → 5P1/2 (Fe = 1, 2) hyperfine transitions of 87Rb (D1 line) is small, and accordingly hyperfine transitions between the ground 5S1/2 (Fg = 2, 3) and excited 5P1/2 (Fe = 2, 3) states of the 85Rb isotope are considerable. These ellipsometric parameters, as phase difference, can trace the behavior of the relative orientation of the electric field and atom velocity in the interface based on van der Waals dipole–dipole interaction and is directly proportional to the strength of the light-matter interaction which extremely useful instead complicated atomic spectroscopic methods.

scholarly journals Polarization Analysis in Mössbauer Reflectometry with Synchrotron Mössbauer Source

2019 ◽  
Vol 4 (1) ◽  
pp. 8 ◽  
Author(s):  
Marina Andreeva ◽  
Roman Baulin ◽  
Aleksandr Chumakov ◽  
Tatiyana Kiseleva ◽  
Rudolf Rüffer
Keyword(s):  
Critical Angle ◽  
Data Interpretation ◽  
Polarization Component ◽  
Magnetic Structures ◽  
Hyperfine Transitions ◽  
Surface Sensitivity ◽  
Reflectivity Spectra ◽  
Ultrathin Layers ◽  
Synchrotron Mössbauer Source ◽  
Selection Of

Polarization selection of the reflected radiation has been employed in Mössbauer reflectivity measurements with a synchrotron Mössbauer source (SMS). The polarization of resonantly scattered radiation differs from the polarization of an incident wave so the Mössbauer reflectivity contains a scattering component with 90° rotated polarization relative to the π-polarization of the SMS for some hyperfine transitions. We have shown that the selection of this rotated π→σ component from total reflectivity gives an unusual angular dependence of reflectivity characterized by a peak near the critical angle of the total external reflection. In the case of collinear antiferromagnetic interlayer ordering, the “magnetic” maxima on the reflectivity angular curve are formed practically only by radiation with this rotated polarization. The first experiment on Mössbauer reflectivity with a selection of the rotated polarization discovers the predicted peak near the critical angle. The measurement of the rotated π→σ polarization component in Mössbauer reflectivity spectra excludes the interference with non-resonant electronic scattering and simplifies the spectrum shape near the critical angle allowing for an improved data interpretation in the case of poorly resolved spectra. It is shown that the selected component of Mössbauer reflectivity with rotated polarization is characterized by enhanced surface sensitivity, determined by the “squared standing waves” depth dependence. Therefore, the new approach has interesting perspectives for investigations of surfaces, ultrathin layers and multilayers having complicated magnetic structures.

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