Room for pH13 and M.Ibrahim

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pH13

08:24

@privetDruzia hello

6 hours later…

M.Ibrahim

13:59

@pH13 Hello :)

pH13

hello

M.Ibrahim

sorry for being late but I have drug design exam tomorrow .

now we concluded that the basis set consists of orhtogonal and non-orthogonal AOs, what is the role of symmetry ?

in other word how can we integrate different AOs from different atoms to test if they obey the same representation ?

Is this a separate calculation ?

pH13

14:21

I'm not that sure about my thought of symmetry right now

you might be right when thinking that he only knows which integrals are zero

M.Ibrahim

do you know another benefit of it ?

pH13

that's a big benefit :D

but no, not really ...

M.Ibrahim

I know that we can make a symmetry adapted linear combination(basis set) using the projection operator, but thing which I don't get is how this can be done for Ab-initio (geometry is unknown) calculations not for semi-empiricals !

pH13

how can you know about symmetry without knowing the geometry?

M.Ibrahim

that is, from this we can say that SALC is not applicable for Ab-initio

But I'm not sure about this

pH13

14:28

then what is ab initio?

M.Ibrahim

Ab-initio means from the beginning, a type of calculation made entirely without experimental (empirical) reference

pH13

I cannot even formulate my question xD

when do you think can ab initio calculations be done? on which systems?

M.Ibrahim

why ? do you have problems with English ?

pH13

I have problems by understanding your problem :)

M.Ibrahim

It can be done for any system but it costs alot of time especially for large systems.

pH13

14:35

and what do you mean by "geometry is unknown" for ab initio?

M.Ibrahim

I think symmetry can be utilized after geometry optimization by Ab-initio.. what do you think ?

pH13

symmetry can be used for geometry optimization if symmetrization has been done before

M.Ibrahim

what is symmetrization ?

pH13

take your geometry and make it symmetric ... don't know the proper english term

M.Ibrahim

do you mean the initial (arbitrary) geometry which is specified by the user's mouse ?

pH13

14:40

yes

M.Ibrahim

and this is not to be considered as empirical aid ?

pH13

yes

M.Ibrahim

great

how much it takes from you to finish your thesis ?

pH13

how much what? time? energy?

M.Ibrahim

time

and energy

pH13

14:44

a lot of energy :D ... and I have to finish it on the 1st of april

M.Ibrahim

what is hard in it ?

pH13

to understand the theory behind it and to connect the calculations with the experimental data

M.Ibrahim

what are the theories you use other than MO and DFT ?

pH13

td-dft

resonance raman

"normal" raman

which all ends up in sth called spectro-electro chemistry

M.Ibrahim

so you are in daily treatment with character tables

pH13

14:49

nope

why should I? :)

M.Ibrahim

It predict the IR and Raman spectrum for the molecules

pH13

a) that does the program and b) my molecule isn't symmetric ^^

M.Ibrahim

aha

What is the thing you to prove or what is the objective of your thesis ?

pH13

it's very general ... qunatum chemical investigations on ruthenium based dyes

there is nothing to prove but to assist experimentalist with understanding their molecules

M.Ibrahim

are you interested in it ?

pH13

14:57

would be bad if not, right?

M.Ibrahim

no you may fall in love with it after a while :D

pH13

it's interesting, yes ... but there are many things that are interesting

M.Ibrahim

how did you get in this field ?

pH13

I wanted to do computational chemistry, was shown some possible themes to work on chose this :)

there was another possibility to work on properties of self-healing polymers ... but I was not sure if I would be able to produce enough data on this during half a year

there are many degrees of freedom during the optimization and that would have taken a lot of time ...

M.Ibrahim

work hard and good luck @pH13 .

pH13

15:05

thx

M.Ibrahim

i have to close now but I will be online soon :)

pH13

good luck for your exam

M.Ibrahim

thank you :)