Ab initio molecular orbital theory is used to determine if the molecular ion HOC+ is linear (as are the isoelectronic species HCN, HNC, HCO+, etc.), or if it is quasilinear. Near the Hartree-Fock limit the molecule is either linear, or very close to linear. Electron correlation favors the linear geometry, leading to the unequivocal prediction of a linear molecule. Detailed comparisons between HOC+ and isoelectronic HNC show an apparent lack of convergence in the bending potential for the former which is remedied by the addition of f functions to the basis set. The HOC+ potential energy surface is computed in the bending and bend-stretch coordinates and fit to an analytical function. Use of this function to compute the rotation-vibration energies results in improved agreement with experiment relative to previous potentials by nearly two orders of magnitude, as documented in the accompanying paper.

中文翻译：

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HOC+ 平衡几何形状和力场的高精度从头算测定

从头算分子轨道理论用于确定分子离子 HOC+ 是线性的（如等电子物质 HCN、HNC、HCO+ 等），还是准线性的。在 Hartree-Fock 极限附近，分子要么是线性的，要么非常接近线性。电子相关性有利于线性几何，导致线性分子的明确预测。HOC+ 和等电子 HNC 之间的详细比较表明，前者的弯曲势明显缺乏收敛，这可以通过向基组添加 f 函数来弥补。HOC+ 势能面在弯曲和弯曲-拉伸坐标中计算，并适合解析函数。