Gaussian basis sets dominate quantum chemistry but struggle to model near-core electron densities and thus nuclear magnetic resonance (NMR) spectral properties. Mixed ramp-Gaussian (RG) basis sets show significant promise for these core properties due to the inclusion of a ramp-function with a non-zero nuclear-electron cusp. To enable quicker testing of the potential of RG basis sets for core chemistry, here we approximate ramps as a large linear combination of Gaussians called pseudoramps, thus enabling standard quantum chemistry packages to be used to approximate RG basis set results. We produce and test rampified general-purpose segmented Jensen basis sets. These basis sets retain the valence chemistry of their parent all-Gaussian basis sets, as desired, but unfortunately fail to show significantly improved performance in core chemistry. Crucially, for NMR spin-spin couplings (the most promising potential application of RG basis sets), general-purpose basis sets are so poorly performing that results cannot be interpreted. For chemical shifts, P-ramps are likely required for improved performance. We conclude that the use of pseudoramps to test the performance of ramp-Gaussian basis sets is extremely helpful, decoupling methodology development and evaluation from implementation, but that more sophisticated basis set optimisation will be required to identify potential advantages of ramp-Gaussian basis sets over all-Gaussian basis sets.

高斯基组在量子化学中占主导地位，但很难对近核电子密度进行建模，从而对核磁共振 (NMR) 光谱特性进行建模。由于包含具有非零核电子尖峰的斜坡函数，混合斜坡高斯 (RG) 基组对这些核心特性显示出显着的前景。为了能够更快地测试 RG 基组对核心化学的潜力，这里我们将斜坡近似为称为伪斜坡的高斯的大型线性组合，从而使标准量子化学包能够用于近似 RG 基组结果。我们生产和测试斜坡化的通用分段 Jensen 基组。这些基组根据需要保留了其父全高斯基组的价化学，但遗憾的是未能在核心化学中显示出显着改善的性能。至关重要的是，对于 NMR 自旋-自旋耦合（RG 基组最有前途的潜在应用），通用基组的性能非常差，以至于无法解释结果。对于化学位移，可能需要 P 斜坡以提高性能。我们得出的结论是，使用伪斜坡测试斜坡高斯基组的性能非常有帮助，将方法学开发和评估与实现脱钩，但需要更复杂的基组优化来识别斜坡高斯基组的潜在优势。全高斯基组。可能需要 P 斜坡来提高性能。我们得出的结论是，使用伪斜坡测试斜坡高斯基组的性能非常有帮助，将方法学开发和评估与实现脱钩，但需要更复杂的基组优化来识别斜坡高斯基组的潜在优势。全高斯基组。可能需要 P 斜坡来提高性能。我们得出的结论是，使用伪斜坡测试斜坡高斯基组的性能非常有帮助，将方法学开发和评估与实现脱钩，但需要更复杂的基组优化来识别斜坡高斯基组的潜在优势。全高斯基组。