Soldán Pavel, Cvitas Marko T, Hutson Jeremy M, Honvault Pascal, Launay Jean-Michel
Department of Chemistry, University of Durham, South Road, England.
Phys Rev Lett. 2002 Oct 7;89(15):153201. doi: 10.1103/PhysRevLett.89.153201. Epub 2002 Sep 18.
Ultracold collisions between spin-polarized Na atoms and vibrationally excited Na2 molecules are investigated theoretically, using a reactive scattering formalism (including atom exchange). Calculations are carried out on both pairwise additive and nonadditive potential energy surfaces for the quartet electronic state. The Wigner threshold laws are followed for energies below 10(-5) K. Vibrational relaxation processes dominate elastic processes for temperatures below 10(-3)-10(-4) K. For temperatures below 10(-5) K, the rate coefficients for vibrational relaxation (v=1-->0) are 4.8x10(-11) and 5.2x10(-10) cm(3) s(-1) for the additive and nonadditive potentials, respectively. The large difference emphasizes the importance of using accurate potential energy surfaces for such calculations.
利用反应散射形式理论（包括原子交换）对自旋极化钠原子与振动激发的Na₂分子之间的超冷碰撞进行了理论研究。在四重电子态的成对加和与非加和势能面上进行了计算。对于低于10⁻⁵K的能量，遵循维格纳阈值定律。对于低于10⁻³ - 10⁻⁴K的温度，振动弛豫过程主导弹性过程。对于低于10⁻⁵K的温度，加和势和非加和势下振动弛豫（v = 1→0）的速率系数分别为4.8×10⁻¹¹和5.2×1⁻¹⁰cm³ s⁻¹。这种巨大差异强调了在此类计算中使用精确势能面的重要性。
