[CP2K-user] What does MULTIPLICITY 0 means?

Matt W mattwa... at gmail.com
Tue Apr 30 11:22:33 UTC 2019


    IF (dft_control%multiplicity == 0) THEN
         IF (MODULO(nelectron, 2) == 0) THEN
            dft_control%multiplicity = 1
         ELSE
            dft_control%multiplicity = 2
         END IF
      END IF

the default zero is just a place holder - gets replaced by 1 or 2 if 
unrestricted and even / odd number of electrons.

Matt

On Tuesday, April 30, 2019 at 10:50:03 AM UTC+1, Torstein Fjermestad wrote:
>
> Dear Matt, 
>
> The part you quote from the manual is very clear. 
> What confuses me is that two lines further down it says "Default value: 0"
> The multiplicity cannot be zero, so I wonder what the value 0 of the 
> keyword MULTIPLICITY means. 
>
> Thanks in advance for clarification. 
> Regards,
> Torstein
>   
>
> mandag 29. april 2019 17.19.19 UTC skrev Matt W følgende:
>>
>> Hi,
>>
>> the online reference manual says
>>
>> "MULTIPLICITY {Integer}
>> Two times the total spin plus one. Specify 3 for a triplet, 4 for a 
>> quartet, and so on. Default is 1 (singlet) for an even number and 2 
>> (doublet) for an odd number of electrons. "
>>
>> so [2S + 1] is the multiplicity you give for multiplicity. Where S is the 
>> total spin angular momentum of the system you want to model.
>>
>> Matt
>>
>>
>> On Monday, April 29, 2019 at 5:26:24 PM UTC+1, Torstein Fjermestad wrote:
>>>
>>> Dear all, 
>>>  
>>> In the Cp2k manual, the explanation for the keyword "MULTIPLICITY" is as 
>>> follows: "*Default is 1 (singlet) for an even number and 2 (doublet) 
>>> for an odd number of electrons."*
>>>
>>> But then two lines further down, it says: "Default value: 0"
>>> What does MULTIPLICITY 0 means? 
>>>
>>> Thanks in advance for your clarification.  
>>>
>>> Regards,
>>> Torstein
>>>
>>>
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