A progress report on the status of the COLUMBUS MRCI program system
A progress report on the status of the COLUMBUS MRCI program system
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关于哥伦布 MRCI 计划系统状态的进度报告
DOI：
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发表时间：
1988
期刊：
影响因子：
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通讯作者：
Jian
中科院分区：
文献类型：
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作者：
R. Shepard;I. Shavitt;R. Pitzer;Donald C. Comeau;Melanie J. M. Pepper;H. Lischka;P. Szalay;R. Ahlrichs;F. B. Brown;Jian
哥伦布程序系统是一个Fortran程序的集合，用于基于图形酉群方法进行一般多参考单激发和双激发组态相互作用（MRSDCI）波函数优化。该程序系统还包括积分生成、SCF和MCSCF轨道优化、积分变换和波函数分析程序。最初的程序系统是在1980年至1981年编写的。从那时起，它已经发展成为计算化学界最流行的MRSDCI程序系统之一。这一演变的讨论将包括利用有效的矩阵矩阵和矩阵向量积计算内核，使用一般收缩的自适应轨道基组，一般的哈密顿对角化程序，基于能量的内部行走选择，灵活的DRT规范，改进的耦合系数评估方法，耦合对功能和多参考CPF的能力，和密度矩阵的建设。在不同地点和不同计算机上维护的程序系统的许多版本现在正在合并。这个组合版本的源代码将提供给计算化学社区。特定计算机的源代码可以通过程序系统中包含的简单过滤器实用程序从另一计算机的源代码生成。直接支持的计算机最初将包括各种型号的VAX、Cray、FPS、IBM、CDC和ETA计算机，此后不久将增加其他计算机。正在进行的发展，讨论的哥伦布系统，包括一个新的方法计算解析能量梯度MRSDCI波函数。这种基于有效密度矩阵的方法避免了每个坐标方向的“耦合扰动MCSCF”解，避免了任何导数积分量从AO到MO基的变换，避免了耦合系数从MO到AO基的变换，允许MCSCF双占据轨道的子集被冻结在CI波函数中，并且允许从不必与MCSCF扩展CSF相关的一般参考CSF生成MRSDCI波函数。
The COLUMBUS program system is a collection of Fortran programs for performing general multireference single- and double-excitation configuration interaction (MRSDCI) wave function optimization based on the graphical unitary group approach. The program system also includes integral generation, SCF and MCSCF orbital optimization, integral transformation, and wave function analysis programs. The original program system was written in 1980 to 1981. Since that time, it has evolved into one of the most popular MRSDCI program systems used in the computational chemistry community. The discussion of this evolution will include the exploitation of efficient matrix-matrix and matrix-vector product computational kernels, the use of generally contracted symmetry-adapted orbital basis sets, general Hamiltonian diagonalization procedures, energy-based internal walk selection, flexible DRT specification, improved coupling-coefficient evaluation methods, coupled-pair functional and multireference CPF capabilities, and density matrix construction. The numerous versions of the program system that are maintained at different sites and on different computers are now in the process of being merged. The source code for this combined version will be made available to the computational chemistry community. The source code for a specific computer may be generated from the source code for another computer by a single pass through a simple filter utility that is included with the program system. The directly supported computers will initially include various models of VAX, Cray, FPS, IBM, CDC, and ETA machines with the addition of other machines shortly thereafter. The ongoing developments of the COLUMBUS system that are discussed include a new method for computing analytic energy gradients for MRSDCI wave functions. This effective-density-matrix based method avoids the “coupled perturbed MCSCF” solutions for each coordinate direction, avoids the transformation of any derivative-integral quantities from the AO to the MO basis, avoids the transformation of the coupling coefficients from the MO to the AO basis, allows a subset of the MCSCF doubly occupied orbitals to be frozen in the CI wave function, and allows the MRSDCI wave function to be generated from general reference CSFs that are not necessarily related to the MCSCF expansion CSFs.