光谱学与光谱分析
光譜學與光譜分析
광보학여광보분석
SPECTROSCOPY AND SPECTRAL ANALYSIS
2014年
11期
2994-2998
,共5页
陈恒杰%郭雷%方旺%贾国柱
陳恆傑%郭雷%方旺%賈國柱
진항걸%곽뢰%방왕%가국주
2,3-二氯吡嗪%振动光谱%势能分布%非谐性分析%密度泛函理论
2,3-二氯吡嗪%振動光譜%勢能分佈%非諧性分析%密度汎函理論
2,3-이록필진%진동광보%세능분포%비해성분석%밀도범함이론
2,3-dichloropyrazine%Vibration spectra%Potential energy distribution%Anharmonic analysis%Density functional the-ory
应用KBr压片法、熔融法分别测定了2，3-二氯吡嗪（2，3-DCP）结晶相和液相下400～4000 cm-1范围内的傅里叶变换红外光谱（FTIR），及其600～4000 cm -1内的傅里叶变换拉曼光谱（FT-Raman）。采用密度泛函（DFT ）理论之B3LYP方法在6-311＋＋G（2df ，2pd）基组水平上优化了该分子的平衡几何结构，基于此结构应用谐性力场计算获得了2，3-DC P的振动频率、红外强度和拉曼活性并进一步计算了直到四阶的非谐性力场，将该力场带入标准旋振哈密顿量并利用二阶微扰理论获得了更加准确的振动频率，相应的红外、拉曼光谱。通过非谐力场获得的振动频率位置结合谐性强度与实验结果比对，对2，3-DC P的各振动带进行了详细指认，采用简正坐标分析方法得到各振动频率的势能分布（PED），首次对2，3-DCP的振动光谱进行了全面归属。结果同时显示：考虑非谐性效应后的理论结果大大提高了振动频率的预测性，用其获得的振动频率能很好的再现实验基频，其与实验值差异大多保持在10 cm-1以下，即使在谐振预期很差的高频区域，考虑非谐效应后这种差异也迅速降低到19 cm -1以下，这对正确归属和预期振动光谱是十分有帮助的。目前的结论也可推广应用到其他分子体系。
應用KBr壓片法、鎔融法分彆測定瞭2，3-二氯吡嗪（2，3-DCP）結晶相和液相下400～4000 cm-1範圍內的傅裏葉變換紅外光譜（FTIR），及其600～4000 cm -1內的傅裏葉變換拉曼光譜（FT-Raman）。採用密度汎函（DFT ）理論之B3LYP方法在6-311＋＋G（2df ，2pd）基組水平上優化瞭該分子的平衡幾何結構，基于此結構應用諧性力場計算穫得瞭2，3-DC P的振動頻率、紅外彊度和拉曼活性併進一步計算瞭直到四階的非諧性力場，將該力場帶入標準鏇振哈密頓量併利用二階微擾理論穫得瞭更加準確的振動頻率，相應的紅外、拉曼光譜。通過非諧力場穫得的振動頻率位置結閤諧性彊度與實驗結果比對，對2，3-DC P的各振動帶進行瞭詳細指認，採用簡正坐標分析方法得到各振動頻率的勢能分佈（PED），首次對2，3-DCP的振動光譜進行瞭全麵歸屬。結果同時顯示：攷慮非諧性效應後的理論結果大大提高瞭振動頻率的預測性，用其穫得的振動頻率能很好的再現實驗基頻，其與實驗值差異大多保持在10 cm-1以下，即使在諧振預期很差的高頻區域，攷慮非諧效應後這種差異也迅速降低到19 cm -1以下，這對正確歸屬和預期振動光譜是十分有幫助的。目前的結論也可推廣應用到其他分子體繫。
응용KBr압편법、용융법분별측정료2，3-이록필진（2，3-DCP）결정상화액상하400～4000 cm-1범위내적부리협변환홍외광보（FTIR），급기600～4000 cm -1내적부리협변환랍만광보（FT-Raman）。채용밀도범함（DFT ）이론지B3LYP방법재6-311＋＋G（2df ，2pd）기조수평상우화료해분자적평형궤하결구，기우차결구응용해성력장계산획득료2，3-DC P적진동빈솔、홍외강도화랍만활성병진일보계산료직도사계적비해성력장，장해력장대입표준선진합밀돈량병이용이계미우이론획득료경가준학적진동빈솔，상응적홍외、랍만광보。통과비해력장획득적진동빈솔위치결합해성강도여실험결과비대，대2，3-DC P적각진동대진행료상세지인，채용간정좌표분석방법득도각진동빈솔적세능분포（PED），수차대2，3-DCP적진동광보진행료전면귀속。결과동시현시：고필비해성효응후적이론결과대대제고료진동빈솔적예측성，용기획득적진동빈솔능흔호적재현실험기빈，기여실험치차이대다보지재10 cm-1이하，즉사재해진예기흔차적고빈구역，고필비해효응후저충차이야신속강저도19 cm -1이하，저대정학귀속화예기진동광보시십분유방조적。목전적결론야가추엄응용도기타분자체계。
Fourier transform infrared (FTIR) spectra of 2 ,3-dichloropyrazine in the region 400~4000 cm-1 were measured under solid state condition using KBr pellets method and liquid state by the melting method ,besides ,a Fourier transform Raman (FT-Raman) spectra in region 600~4 000 cm -1 was recorded .Then equilibrium geometry of 2 ,3-DCP was optimized ,and based on this ,the harmonic vibrational frequencies ,infrared intensities and Raman activities were calculated using B3LYP method of the density function theory (DFT) in conjunction with 6-311+ + G(2df ,2pd) basis set ,furthermore ,a comprehensive anharmonic calculation was also been performed for obtaining more accurate vibrational frequencies using second-order perturbation theory treatment based on quadratic ,cubic and quartic force constants .Infrared and Raman spectra were simulated corresponding to theory .Experimental FTIR and FT-Raman bands were compared with those positions of peaks obtained from anharmonic calcu-lations and intensities or activities from harmonic carefully .Each vibrational band was assigned and interpreted in detail with help of potential energy distribution (PED) for the first time .In addition ,it was shown that anharmonic results exactly reproduced to experimental data ,improved the validity of prediction greatly in vibration frequencies ,discrepancies between anharmonic and ex-perimental results were limited to below 10 cm -1 in most of vibrational bands ,even if in the high energy regions ,which have a poor performance for hanmonic calculation ,and these differences would be decreased to lower than 19 cm -1 .It is extremely helpful for assigning and predicting vibrational spectra .Present conclusion can be expanded to others molecular systems .
