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liuxianlv

金虫 (正式写手)

[交流] 【求助】分子A和B的opt+freq结果不同 已有2人参与

以下是分子A和B的opt+freq,1,A优化后是4个YES频率计算后却变为2个YES了;B是优化后是4个YES频率计算后仍为4个YES;2,AB分子优化结束都是-- Stationary point found.而频率计算结束时AB不同,A没有-- Stationary point found.而B有-- Stationary point found.

我的疑问:1、A分子这样的结果可用吗?2、A分子为什么会变成2个YES,(优化时已经算了,频率算时为什么还要再 Optimization completed.
-- Stationary point found.)3、A频率结束没有Stationary point found是不是意味着没找到稳定点。4、AB为什么会有差异?

分子A的opt+freq
%nprocshared=4
Will use up to    4 processors via shared memory.
%rwf=LOC1,2000MB,LOC2,2000MB,LOC3,2000MB,LOC4,2000MB,LOC5,2000MB,LOC6,2000MB,LOC
7, 2000MB,LOC8, 2000MB
%mem=200MW
%chk=D:\Data1\Scratch\ams.chk
Default route:  MaxDisk=40GB
----------------------------------------------------
#p opt freq b3lyp/6-31g(d) geom=connectivity pop=reg
----------------------------------------------------
..........................................................................
省略
...........................................................................
优化计算

Item               Value     Threshold  Converged?
Maximum Force            0.000036     0.000450     YES
RMS     Force            0.000009     0.000300     YES
Maximum Displacement     0.000116     0.001800     YES
RMS     Displacement     0.000026     0.001200     YES
Predicted change in Energy=-8.960091D-07
Optimization completed.
    -- Stationary point found.
..........................................................................
省略
...........................................................................
Leave Link 9999 at Thu Jun 10 03:25:03 2010, MaxMem=  209715200 cpu:       0.0
Job cpu time:  0 days  9 hours 39 minutes 58.0 seconds.
File lengths (MBytes):  RWF=    439 Int=      0 D2E=      0 Chk=     12 Scr=      1
Normal termination of Gaussian 03 at Thu Jun 10 03:25:03 2010.
(Enter C:\G03W\l1.exe)
Link1:  Proceeding to internal job step number  2.
------------------------------------------------------------------
#P Geom=AllCheck Guess=Read SCRF=Check GenChk RB3LYP/6-31G(d) Freq
------------------------------------------------------------------
频率计算
..........................................................................
省略
...........................................................................
Item               Value     Threshold  Converged?
Maximum Force            0.000036     0.000450     YES
RMS     Force            0.000009     0.000300     YES
Maximum Displacement     0.056686     0.001800     NO
RMS     Displacement     0.019196     0.001200     NO
Predicted change in Energy=-2.951346D-06
GradGradGradGradGradGradGradGradGradGradGradGradGradGradGradGradGradGrad
..........................................................................
省略
............................................................................
Job cpu time:  0 days  4 hours 25 minutes 33.0 seconds.
File lengths (MBytes):  RWF=    489 Int=      0 D2E=      0 Chk=     12 Scr=      1
Normal termination of Gaussian 03 at Thu Jun 10 07:50:37 2010.

另一个分子分子B的opt+freq
..........................................................................
省略输入文件
...........................................................................

    Item               Value     Threshold  Converged?
Maximum Force            0.000022     0.000450     YES
RMS     Force            0.000006     0.000300     YES
Maximum Displacement     0.001759     0.001800     YES
RMS     Displacement     0.000337     0.001200     YES
Predicted change in Energy=-3.095954D-08
Optimization completed.
    -- Stationary point found.
..........................................................................
省略
...........................................................................
Job cpu time:  0 days  2 hours 15 minutes 25.0 seconds.
File lengths (MBytes):  RWF=    439 Int=      0 D2E=      0 Chk=      7 Scr=      1
Normal termination of Gaussian 03 at Tue Jun 08 14:37:20 2010.
(Enter C:\G03W\l1.exe)
Link1:  Proceeding to internal job step number  2.
------------------------------------------------------------------
#P Geom=AllCheck Guess=Read SCRF=Check GenChk RB3LYP/6-31G(d) Freq优化结束频率开始
------------------------------------------------------------------
..........................................................................
省略
...........................................................................

Item               Value     Threshold  Converged?
Maximum Force            0.000022     0.000450     YES
RMS     Force            0.000006     0.000300     YES
Maximum Displacement     0.001174     0.001800     YES
RMS     Displacement     0.000298     0.001200     YES
Predicted change in Energy=-2.355722D-08
Optimization completed.
    -- Stationary point found.

..........................................................................
省略
...........................................................................

Job cpu time:  0 days  0 hours 43 minutes  3.0 seconds.
File lengths (MBytes):  RWF=    439 Int=      0 D2E=      0 Chk=      7 Scr=      1
Normal termination of Gaussian 03 at Tue Jun 08 15:20:24 2010.
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qzhaosdu

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小木虫(金币+0.5):给个红包,谢谢回帖交流
heyo_123(金币+1):鼓励交流!! 2010-06-13 11:02:06
频率算完了再算一步优化时为了验证得到的结构是否真的是最小。因为在优化的过程中,除非使用CalcAll,那么都是用一阶导数去外推二阶导数,得到的二阶导数不一定是正确的。所以程序最后要验证一下。
Anewday,anewhour,anewminute,anewpeople.
3楼2010-06-12 13:17:52
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lihb734

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小木虫(金币+0.5):给个红包,谢谢回帖交流
aylayl08(金币+2):谢谢 2010-06-12 10:13:50
New Gaussian users are often surprised to see that the final part frequency calculation output that looks that of a geometry optimization at the beginning of a frequency job:

GradGradGradGradGradGradGradGradGradGradGradGradGradGradGrad
Berny optimization.
Initialization pass.Link 103, which performs geometry optimizations, is executed at the beginning and end of all frequency calculations. This is done so that the quadratic optimization step can be computed using the correct second derivatives.
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2楼2010-06-12 08:28:28
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