scholarly journals Feedback Cooling of a Room Temperature Mechanical Oscillator close to its Motional Ground State

2019 ◽  
Vol 123 (22) ◽  
Author(s):  
Jingkun Guo ◽  
Richard Norte ◽  
Simon Gröblacher
Keyword(s):  
Ground State ◽  
Room Temperature ◽  
Mechanical Oscillator

Room-Temperature Chemical Synthesis of C2

2019 ◽  
Author(s):  
Kazunori Miyamoto ◽  
Shodai Narita ◽  
Yui Masumoto ◽  
Takahiro Hashishin ◽  
Mutsumi Kimura ◽  
...  
Keyword(s):  
Chemical Synthesis ◽  
Ground State ◽  
Room Temperature ◽  
Chemical Species ◽  
Quadruple Bond ◽  
Photon Excitation ◽  
Physical Energy ◽  
Theoretical Predictions ◽  
Carbon Arc ◽  
Inherent Nature

Diatomic carbon (C<sub>2</sub>) is historically an elusive chemical species. It has long been believed that the generation of C<sub>2 </sub>requires extremely high “physical” energy, such as an electric carbon arc or multiple photon excitation, and so it has been the general consensus that the inherent nature of C<sub>2 </sub><i>in the ground state </i>is experimentally inaccessible. Here, we present the first “chemical” synthesis of C<sub>2 </sub>in a flask at <i>room temperature or below</i>, providing the first experimental evidence to support theoretical predictions that (1) C<sub>2 </sub>has a singlet biradical character with a quadruple bond, thus settling a long-standing controversy between experimental and theoretical chemists, and that (2) C<sub>2 </sub>serves as a molecular element in the formation of sp<sup>2</sup>-carbon allotropes such as graphite, carbon nanotubes and C<sub>60</sub>.

scholarly journals Realization of Ground-State Artificial Skyrmion Lattices at Room Temperature

2016 ◽  
Author(s):  
Dustin A. Gilbert ◽  
Brian B. Maranville ◽  
Andrew L. Balk ◽  
Brian J. Kirby ◽  
Peter Fischer ◽  
...  
Keyword(s):  
Ground State ◽  
Room Temperature

Ab initio studies on amides: conformational preferences of formimide and barriers to interconversion of the conformers

1980 ◽  
Vol 33 (8) ◽  
pp. 1635 ◽  
Author(s):  
L Radom ◽  
NV Riggs
Keyword(s):  
Ground State ◽  
Room Temperature ◽  
Geometry Optimization ◽  
Basis Set ◽  
Partial Geometry ◽  
Electrostatic Repulsion ◽  
Full Geometry Optimization ◽  
Vapour State ◽  
Conformational Preferences ◽  
Model Transition

Formimide (diformamide), the parent of the diacylamines, is capable of existing in three basic ground-state conformations about the N-C bonds. Full geometry optimization with the STO-3G basis set predicts that all three conformers are fully coplanar, that the E,E (1) and E,Z(3) conformers are of similar energy, and that the Z,Z (2) conformer is of somewhat higher energy (by 11 kJ mol-1); 4-31G evaluation of the energies suggests that (2) is by far the least stable and that (1) is of higher energy than (3) by 6.5 kJ mol-1. Analysis of the calculated charge distribution suggests that (2) is destabilized by electrostatic repulsion. These results are consistent with experimental conclusions that planar (3) is strongly preferred in the vapour state at room temperature and that (2) has not been observed in the vapour state or in solution. Partial geometry optimization with the STO-3G basis set of model transition states for internal rotation suggests a barrier height of 52 kJ mol-1 (72 kJ mol-1 when evaluated with the 4-31G basis set) for the conversion (3) → (1).

scholarly journals Quantum Correlations of Light from a Room-Temperature Mechanical Oscillator

2017 ◽  
Vol 7 (3) ◽  
Author(s):  
V. Sudhir ◽  
R. Schilling ◽  
S. A. Fedorov ◽  
H. Schütz ◽  
D. J. Wilson ◽  
...  
Keyword(s):  
Room Temperature ◽  
Quantum Correlations ◽  
Mechanical Oscillator

5d and 4f electron configuration of CeB6 at 340 and 535 K

2008 ◽  
Vol 64 (5) ◽  
pp. 534-549 ◽  
Author(s):  
Ryoko Makita ◽  
Kiyoaki Tanaka ◽  
Yoshichika Ōnuki
Keyword(s):  
Electron Transfer ◽  
Crystal Field ◽  
Ground State ◽  
Room Temperature ◽  
Atomic Orbital ◽  
Energy Levels ◽  
Electron Configuration ◽  
Acta Cryst ◽  
X Ray ◽  
The Difference

X-ray atomic orbital (XAO) analysis revealed that at both temperatures the electrons are transferred from B 2px (= py ) to Ce 5d and 4f orbitals. At 340 K 5d(j = 5/2)Γ8 orbitals are occupied partially, but 4f(j = 5/2)Γ8 orbitals are more populated than 4f(j = 5/2)Γ7 orbitals, in contrast to our observation at 430 K [Makita et al. (2007). Acta Cryst. B63, 683–692]. At 535 K the XAO analysis revealed clearly that the order of the energy levels of 4f(j = 5/2)Γ8 and Γ7 states reversed again and is the same as that at room temperature. It also limited the possible 5d configurations to three models among the nine possible ones. However, the XAO analysis could not decide which of the three models was the best with the present accuracy of the measurement. Two of them have partially and fully occupied 5d(j = 5/2)Γ7 orbitals and the remaining one has a fully occupied 5d(j = 3/2)Γ8 orbital. Since the lobes of 5d(j = 3/2)Γ8 or 5d(j = 5/2)Γ7 orbitals do not overlap with the 4f(j = 5/2)Γ8 orbitals as well as the 5d(j = 5/2)Γ8 orbitals, the order of the energy levels of the 4f(j = 5/2) orbitals became the same as that at room temperature. These results indicate that the crystal field varies with temperature due to the electron transfer from B 2p to Ce 5d orbitals. The difference densities after the spherical-atom refinement at the three temperatures clearly revealed the different combinations of 4f and 5d orbitals which are occupied. In the present study positive peaks due to the 4f electrons appear near the Ce nucleus and those due to 5d orbitals are found in the area outside the 4f peaks. Between the two areas there is a negative area distributed spherically at 340 K. The negative area produced by the contraction of 4f(j = 5/2)Γ8 orbitals seems to reduce the electron repulsion of the 5d(j = 5/2)Γ8 orbitals and helps the 4f(j = 5/2)Γ8 orbitals to remain as the ground state.

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