[DFTB-Plus-User] analytical second derivative

[常盤広明]

Dear Jan,

Thank you so much for quick response.

I know that "numerical" Hessian is available in DFTB+ program.
But, in general, numerical Hessian is not enough accurate,
especially small amount frequency mode.

I want to use "analytical" Hessian, if possible.

In this version analytical Hessian has not yet available?

Regards,


2013/9/26 Jan Knaup <janknaup at gmail.com>:
> Dear Tokiwa-san,
>
> DFTB+ does not offer analytical second derivatives. However, you can
> numericlly calculate the Hessian matrix using the SecondDerivatives{}
> driver. It is described in detail in the manual. Since the numerical
> derivation is quite slow, I am not sure if this will be fast enough for a
> transition state search.
>
> Best,
> Jan
>
> Jan M. Knaup                      | Fon +49-(0)421-218-62351
> Dipl. Phys. Dr. rer. nat.         | Fax +49-(0)421-218-62770
> Universität Bremen - BCCMS        |
> Am Fallturm 1                     | Jan.Knaup at bccms.uni-bremen.de
> 28359 Bremen                      | JanKnaup at gmail.com
> Germany                           | www.bccms.uni-bremen.de
>
>
> 2013/9/25 常盤広明 <tokiwa at rikkyo.ac.jp>
>>
>> Dear DFTB+ developer:
>>
>> Hello,
>>
>> I try to determined transition states by using the DFTB calculations.
>> So, I would like to calculate "analytical" second energy derivative
>> (Hessian)
>> by the DFTB method.
>> Is it possible?
>>
>> Best Regards,
>>                                   Hiroaki TOKIWA, Rikkyo University
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>
>
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