Koller M, Jung F, Phrompao J, Zeppenfeld M, Rabey I M, Rempe G
Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany.
Phys Rev Lett. 2022 May 20;128(20):203401. doi: 10.1103/PhysRevLett.128.203401.
Reaching high densities is a key step toward cold-collision experiments with polyatomic molecules. We use a cryofuge to load up to 2×10^{7} CH_{3}F molecules into a boxlike electric trap, achieving densities up to 10^{7}/cm^{3} at temperatures around 350 mK where the elastic dipolar cross section exceeds 7×10^{-12} cm^{2}. We measure inelastic rate constants below 4×10^{-8} cm^{3}/s and control these by tuning a homogeneous electric field that covers a large fraction of the trap volume. Comparison to ab initio calculations gives excellent agreement with dipolar relaxation. Our techniques and findings are generic and immediately relevant for other cold-molecule collision experiments.
达到高密度是开展多原子分子冷碰撞实验的关键一步。我们使用一台低温离心机将多达2×10⁷个CH₃F分子加载到一个盒状电阱中，在温度约为350 mK时实现了高达10⁷/cm³的密度，此时弹性偶极截面超过7×10⁻¹² cm²。我们测量了低于4×10⁻⁸ cm³/s的非弹性速率常数，并通过调节覆盖大部分阱体积的均匀电场来控制这些常数。与从头算计算结果的比较表明，在偶极弛豫方面两者吻合得非常好。我们的技术和发现具有通用性，对其他冷分子碰撞实验具有直接的参考价值。
