| Summary: | 碩士 === 國立臺灣大學 === 應用力學研究所 === 107 === The first section is establishing intermolecular database by quantum chemistry. Because intermolecular force is necessary in many fields. Over five decades, the new quantum chemistry methods and equipments that improve the result. In many cases, the result be determined by experimental ways cannot be directly got parameterized value. Thus, it is important to create a database. Its function is conveniently parameterized application and test. In the past research, someone established the database of dimers. The dimers which are common functional groups contain hydrocarbon (alkane, alkene, alkyne),weak hydrogen bond types(alcohol, aldehyde, ketone), strong hydrogen bond types (acid and amide). To complete this database, intermolecular energy of the bimers are our computing objects. The bimers means different molecular dimers (such as methane to ethane ). Using Gaussian09 to simulate the configuration of bimers and calculate intermolecular forces, we used MP2 way with Dunning’s basis sets. Besides, we also used coupled cluster ways (CCSD(T)) to calculate interaction energy. At last, we used Complete Basis Set limit to compare with each ab initio method result. we discussed CBS convergence in relationship with increasing basis set .
After established the database of bimers , we discovered the number of calculations of bimers is more than dimers. we would like to estimate the energy and position of bimers by using the energy and position of dimers. This will greatly reduce computing resources and time. The past research mixing rule is mostly used in atomic systems or spheroidal molecules. This research uses the Boltzmann distribution to apply molecular to mixing rule. The results obtained using the mixing rule are compared with the results of quantum chemistry and collated to find the best mixing rule.
The third part : After the database of bimers is constructed, we used SAPT method to dismantle the intermolecular interaction to some parts like exchange、induction、dispersion、electrostatic terms. We further analyze the repulsive force terms and attractive force terms of bimers. To get the construct of intermolecular energy, and we also want to realize the SAPT results to find the four terms are from which molecular segmental group interaction of bimers.
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