Mridula Guin
mridula.guin@gmail.com
On Mon Jul 20 '15 1:07am, Alex Granovsky wrote
----------------------------------------------
>Hello,
>The excluded frequency is imaginary (this frequency is marked as
>negative in the printout section). This means that your structure
>is not a minimum on a PES but rather is a saddle point on a PES.
>What is the magnitude of the imaginary/negative frequency?
>Kind regards,
>Alex Granovsky
>
>
>On Fri Jul 17 '15 8:33am, Mridula Guin wrote
>--------------------------------------------
>>Dear firefly users
>>During performing frequency calculation, in the thermochemistry section for an optimized geometry I am getting an imaginary frequency which is excluded. My question is whether the structure is stable or not? You can have a look to the part of the logfile below. Please help me to understand this.
>>Thanks in advance..
>>-------------------------------
>> THERMOCHEMISTRY AT T= 298.15 K
>> -------------------------------
>>
>>
>>
>> USING IDEAL GAS, RIGID ROTOR, HARMONIC NORMAL MODE APPROXIMATIONS.
>> P= 1.01325E+05 PASCAL.
>> ALL FREQUENCIES ARE SCALED BY 1.00000
>> THE MOMENTS OF INERTIA ARE (IN AMU*BOHR**2)
>> 480.71546 2956.60067 3437.31425
>> THE ROTATIONAL SYMMETRY NUMBER IS 1.0
>> THE ROTATIONAL CONSTANTS ARE (IN GHZ)
>> 3.75084 0.60985 0.52456
>> 1 IMAGINARY FREQUENCY VIBRATION(S) IS(ARE) EXCLUDED
>> FROM THE FOLLOWING THERMOCHEMICAL ANALYSIS.
>> THE HARMONIC ZERO POINT ENERGY IS (SCALED BY 1.000)
>> 0.127532 HARTREE/MOLECULE 27990.070745 CM**-1/MOLECULE
>> 80.027708 KCAL/MOL 334.835932 KJ/MOL
>>