Efficient rotational cooling of Coulomb-crystallized molecular ions by a helium buffer gas
Efficient rotational cooling of Coulomb-crystallized molecular ions by a helium buffer gas
复制标题
通过氦缓冲气体对库仑结晶分子离子进行高效旋转冷却
DOI：
10.1038/nature12996
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发表时间：
2014
期刊：
影响因子：
64.8
通讯作者：
… Schwarz
中科院分区：
文献类型：
--
作者：
Hansen;… Schwarz
冷分子的制备在基础物理研究、复杂分子的高分辨光谱、冷化学和天体化学等领域具有重要意义。一种广泛应用的冷却分子的通用方法是氦缓冲气体冷却，无论是在超音速束扩张中，还是在低温陷阱环境中。另一种适用于捕获分子离子的较新方法依赖于交感平移冷却，通过与共捕获的激光冷却原子离子的碰撞作用，形成称为库仑晶体的空间有序结构，并结合激光控制的内态制备。本文给出了在低温线性射频四极陷阱中俘获并交感冷却的分子离子转动自由度的氦缓冲气体冷却实验结果。由于氦的碰撞速率仅为每秒十个左右--即比典型的缓冲气体冷却环境低四到五个数量级--我们已经将单个分子离子冷却到开尔文的旋转温度，这是迄今为止测量到的最低温度。此外，通过改变较大库仑晶体中原子和分子离子的形状或数量，或两者兼而有之，我们通过改变离子的平移微动能，将有效旋转温度从约7Kelvin调整到约60Kelvin。极低的氦碰撞率可能允许单分子离子的交感边带冷却，最终使缓冲气体冷却分子离子的量子逻辑光谱成为可能。此外，将目前的冷却方案应用于复杂的分子离子，应该能够对生物感兴趣的单个分子进行单态或少态操纵。
The preparation of cold molecules is of great importance in many contexts, such as fundamental physics investigations,, high-resolution spectroscopy of complex molecules,,, cold chemistry, and astrochemistry. One versatile and widely applied method to cool molecules is helium buffer-gas cooling in either a supersonic beam expansion, or a cryogenic trap environment,. Another more recent method applicable to trapped molecular ions relies on sympathetic translational cooling, through collisional interactions with co-trapped, laser-cooled atomic ions, into spatially ordered structures called Coulomb crystals, combined with laser-controlled internal-state preparation,,,,,,,,,,,,. Here we present experimental results on helium buffer-gas cooling of the rotational degrees of freedom of MgH+ molecular ions, which have been trapped and sympathetically cooled in a cryogenic linear radio-frequency quadrupole trap. With helium collision rates of only about ten per second—that is, four to five orders of magnitude lower than in typical buffer-gas cooling settings—we have cooled a single molecular ion to a rotational temperature of kelvin, the lowest such temperature so far measured. In addition, by varying the shape of, or the number of atomic and molecular ions in, larger Coulomb crystals, or both, we have tuned the effective rotational temperature from about 7 kelvin to about 60 kelvin by changing the translational micromotion energy of the ions. The extremely low helium collision rate may allow for sympathetic sideband cooling of single molecular ions, and eventually make quantum-logic spectroscopy of buffer-gas-cooled molecular ions feasible. Furthermore, application of the present cooling scheme to complex molecular ions should enable single-or few-state manipulations of individual molecules of biological interest,.
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影响因子：
4.4
作者：
T. Rizzo;Y. Park;L. Peteanu;D. Levy
通讯作者：
D. Levy
DOI：
--
发表时间：
2008
期刊：
影响因子：
--
作者：
Ian W. M. Smith
通讯作者：
Ian W. M. Smith
低温保罗陷阱中 MgH 第一振动激发态的衰减率测量。
影响因子：
8.6
作者：
O. Versolato;M. Schwarz;A. K. Hansen;A. Gingell;A. Windberger;L. Kłosowski;J. Ullrich;F. Jensen;José R. Crespo López;M. Drewsen
通讯作者：
M. Drewsen
影响因子：
16.6
作者：
Hansen, Anders K.;Sorensen, Magnus A.;Drewsen, Michael
通讯作者：
Drewsen, Michael
影响因子：
1.8
作者：
Kamrath, Michael Z.;Relph, Rachael A.;Johnson, Mark A.
通讯作者：
Johnson, Mark A.