Immirzi Attilio
Dipartimento di Chimica, Università di Salerno, Fisciano, Salerno, Italy.
J Chem Inf Model. 2007 Nov-Dec;47(6):2263-5. doi: 10.1021/ci700225x. Epub 2007 Oct 31.
A molecular modeling procedure, based on internal coordinates and strictly analytical even in the most intricated cases, is described. Internal coordinates, always nonredundant, become mutually independent and can be varied without constraints. Structural refinement from diffraction data (Least-square method, LS) can be done using the classical Gauss-Newton approach and avoiding Lagrange multipliers. A comparative test done using published data has shown that while the new method gives rise to a structural refinement in perfect agreement with the known structure, the traditional methods (z-matrix and constraints based) does not work.
描述了一种基于内坐标的分子建模程序，即使在最复杂的情况下也完全是解析性的。内坐标始终是非冗余的，相互独立且可以无约束地变化。可以使用经典的高斯 - 牛顿方法并避免拉格朗日乘数来根据衍射数据进行结构精修（最小二乘法，LS）。使用已发表的数据进行的对比测试表明，虽然新方法能产生与已知结构完全一致的结构精修结果，但传统方法（基于z矩阵和约束的方法）却行不通。
