在第二部分中，我們以SIESTA進行了CN-CH=CH-NH2、NO2-CH=CH-NH2與BH2-CH=CH-NH2¬這三個推拉電子基分子系統的第一原理分子動態模擬，並且蒐集了3ps下的電偶極矩、結構以及電荷的動態資訊。我們將電偶極矩的自動相關函數透過傅立葉轉換後，模擬出紅外線振動光譜，並搭配著PaDAF與SCAF的光譜解析方案成功的分析出分子中特徵官能基振動頻率，並與FTIR實驗的結果相近。同時利用了電荷自動相關函數透過傅立葉轉換後所得到的FT[charge-ACF]光譜，與紅外線振動光譜比對，建立了電荷轉移與分子運動的關聯性，並且指出造成電荷轉移的特定官能基運動模式。此外，透過了推電子基與拉電子基的電荷動態觀察，我們根據電荷的震盪程度大小估算出電荷轉移的速率，說明這三個分子的電荷轉移效應。最後，我們針對了CN-CH=CH-NH2的系統做了溫度效應的探討，同時計算出分子的熱誘導電荷轉移的活化能大小。 Abstract: In part 1 , total energy calculation based on Density Function Theory (DFT) with Ultrasoft-pseudopotenital and generalized gradient spin-polarized approximation (GGSA) was used to investigate (1) O-H cleavage of ethanol and (2)C-H hydrogen elimination via four-membered ring and five-membered ring on Pt(111)-3x3 surface. By means of Partial Structure Constrain Path Minimization(PSCPM) method , our calculated energy barrier for O-H cleavage is 0.849eV and C-H hydrogen elimination via four-membered ring and five-membered ring are 0.319eV and 0.966eV , respectively. These results are in good agreement with TPD experimental result. Furthermore , we found that (1) less change in Pt-Pt dimmer bond length and (2) more H-Pt bond formation , less change in carbon hybrid orbital and π bonding in C=O by means of the partial density of state (PDOS) for the four-membered-ring hydrogen elimination to explain reaction selectivity.
In part 2 , we performed first principle molecular dynamics based on Density Function Theory with norm-conversing pseudopotential and accurate LCAO basis set in SIESTA package on CN-CH=CH-NH2 , NO2-CH=CH-NH2 and BH2-CH=CH-NH2¬ push-pull molecule system and we collected dipole moment ,structure and charge trajectory in 3ps molecular dynamics. We used Fourier Transformed dipole moment AutoCorrelation Function to simulate IR spectra and analyzed characteristic vibration mode in molecule by using PaDAF and SCAF method. By comparison of Fourier Transformed charge AutoCorrelation Function (FT[charge-ACF]) and IR spectra , we found that main-chain vibration mode induced charge transfer. Furthermore , we calculated charge transfer rate by utilizing charge dynamics and explain charge transfer effect of these push-pull molecules.Finally , we also investigated temperature effect on charge transfer and calculated activation barrier of charge transfer.
