FIST - Morse coulombic subtraction and Genpot Funtion units

[ganta.pra... at gmail.com]

Hi Zuohen,

I think it is not implemented in CP2K yet (not sure), so I am using 
different water model that does not require coulombic subtraction. 

Have a nice day.

Thanks and Regards,
Prasanth. 

On Monday, March 12, 2018 at 1:07:22 PM UTC+1, zuoh... at gmail.com wrote:
>
> I have the same question. Did you implement the coulombic subtraction for 
> morse potential successfully?
>
> 在 2017年11月20日星期一 UTC+8上午6:38:15，ganta.... at gmail.com写道：
>>
>> Dear CP2K team/users,
>>
>> I am trying to use FIST to do GEO_OPT of a box of water molecules. I have 
>> following doubts.
>>
>> 1) How to implement coulombic subtraction in &BONDED --> Morse potential.
>>
>> In CP2K the morse potential is in the form
>>
>> *K1*[(1-exp(-K2*(R-R0)))^2-1])* 
>>
>> But I want to include coulombic subtraction and implement the below form. 
>>
>> *K1*[(1-exp(-K2*(R-R0)))^2-1]) - D*Q1*Q2/R*
>>
>> where Q1 and Q2 are charges of the atoms.
>>
>> Please let me know if it is possible. 
>>
>> 2) What will be the units of the FUNCTION for below case. Will it be eV 
>> or CP2K internal  units? Do we need to adjust the FUNCTION expression 
>> manually to match the CP2K internal units (atomic units) ? Please let me 
>> know. 
>>
>>          &GENPOT                                                        
>>                                                                 
>>           ATOMS OWAT OWAT                                                
>>                                                               
>>           FUNCTION ((A/(r^12))-(B/(r^6)))                                
>>                                                               
>>           PARAMETERS A B                                                  
>>                                                              
>>           UNITS eV*angstrom^12 eV*angstrom^6                              
>>                                                              
>>           VALUES  39344.98  42.15                                        
>>                                                               
>>           VARIABLES r                                                    
>>                                                               
>>           RCUT [angstrom] $WATERCUTOFF                                    
>>                                                              
>>         &END GENPOT     
>>
>> Have a nice day.
>>
>> Thanks and Regards,
>> Prasanth.                                                 
>>
>
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