We introduce ULYSSES, a user-friendly and robust C++ library for semiempirical quantum chemical calculations. In its current version, ULYSSES is equipped with a large set of different semiempirical models, most of which are based on the Neglect of Diatomic Differential Overlap (NDDO) approximation. Empirical corrections for dispersion and hydrogen bonding are available for most methods, so that higher quality is achieved in the calculation of energies of nonbonded complexes. The library is furthermore equipped with geometry optimization, as well as modules for calculating molecular properties of general interest. Ideal gas thermodynamics is available and allows single structure as well as conformer (multistructure) averaged properties to be calculated. We offer the possibility to use several vibrational partition functions according to the nature of interactions being studied: for covalent systems, the traditional harmonic oscillator approximation is available; for nonbonded complexes, we systematically extended the partition function proposed by Grimme for all thermodynamic functions. The library is also capable of running Born–Oppenheimer molecular dynamics.

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ULYSSES：一个高效且易于使用的 C++ 半经验库

我们介绍了ULYSSES，这是一个用户友好且强大的C++库，用于半经验量子化学计算。在其当前版本中，ULYSSES配备了大量不同的半经验模型，其中大部分基于忽略双原子微分重叠 (NDDO) 近似。大多数方法都可以对色散和氢键进行经验校正，从而在计算非键合配合物的能量时获得更高的质量。该库还配备了几何优化，以及用于计算普遍感兴趣的分子特性的模块。理想气体热力学是可用的，并允许计算单一结构以及构象异构体（多结构）的平均特性。我们提供了根据所研究的相互作用的性质使用几种振动配分函数的可能性：对于共价系统，可以使用传统的谐振子近似；对于非键合配合物，我们系统地扩展了 Grimme 提出的所有热力学函数的配分函数。该库还能够运行 Born-Oppenheimer 分子动力学。