Theoretical Chemistry

The use of mathematical and computational methods to build theories explaining observations of chemical reactions, such as quantum chemistry. | Contact experts in Theoretical Chemistry to get answers

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Questions related to Theoretical Chemistry

How to define parameters for solvent Trifluoroethanol for SCRF run using Gaussian ?

I want to perform calculation in solvent 2,2,2-Trifluoroethanol in gaussian but its not defined in gaussian. Please help me out how should I proceed for the same.

02 February 2017 5,763 5 View

How to calculate MM charges for a biomacromolecule?

I optimized a biomacromolecule with UFF method, then used IOp and pop=esp keywords for calculate biomacromolecule partial charges, these charges as QEq charges were calculated in .log file. But...

02 February 2017 8,829 6 View

Is it possible to investigate a transition sate using excited state calculation?

I am working in an investigation of photochemistry reaction in which corresponding to ground state and excited state calculations. Then I want to study the transition sate which locates on an...

02 February 2017 6,252 2 View

How computational study of CH functionalization esp gaussian 09. plse attache some relevant papers or articles which help my study?

Is there any one who know about how computational study of CH functionalization esp gaussian 09. plse attache some relevant papers or articles which help my study

02 February 2017 5,077 0 View

How do I remove imaginary frequencies when optimising geometries in Gaussian 09?

I am attempting to remove imaginary frequencies (negative frequencies) from the ground state optimisations I am carrying out using Gaussian 09. Currently, I am using the UltraFine grid. I have...

02 February 2017 1,940 2 View

About geometry optimization of na(h2o)6 in zeolite structure?

Hi, I'm a gaussian 09 user. Recently, I tried to calculate optimization of na(h2o)6 in zeolite structure. I started this calculation using M06-2X theory level, and 6-31+G(d):mndo basis...

02 February 2017 1,884 3 View

Can Dmol3 display intermediate geometries during geometry optimization?

Dear All, How can I monitor intermediate geometries during geometry optimization task in Dmol3? As far as I know, it only shows the final geometry.Is there any way to see them? Thank you so much

02 February 2017 8,331 5 View

How to calculate the solvation energy of hydrogen atom in Gaussian 9?

I am using 6-311++g(2df,p) basis set and CPCM model for acetonitrile. Is there any command I could use or can I find this piece of information in output file.

02 February 2017 7,664 8 View

How does one do a loop in Gaussian?

Hello, thank you for your help. So first of all I have a lot of .gjf files (Gaussian acceptable format) and I want to run Gaussian on all of them to get energy log files. I think that's a...

02 February 2017 7,986 6 View

Is it possible to open an incomplete Gaussian checkpoint file in GView?

If you perform a restart on any Gaussian job it will write over the contents of the earlier .log/.out file. Typically, an incomplete log./.out file can be loaded in GView showing the results thus...

02 February 2017 1,373 4 View

How to run natural energy decomposition analysis in Gamess with b3lyp/6-311++g(d,p) basis sets?

I carry out the natural energy decomposition analysis (NEDA) on gamess with b3lyp/6-311++g(d,p) level for the complex in the less distances of the local minimum but unfortunately, the output is...

02 February 2017 5,808 2 View

Help with using DFT to model reduced metal complexes?

I am currently trying to optimise the geometry of a group of reduced metal complexes and am having trouble with a few of the methods I am using for these calculations. I am using 4 methods:...

02 February 2017 9,802 6 View

TS calculation in Gaussian leads to too many imaginary frequencies?

I am trying to find a transition state for a nucleophile addition and my jobs never seem to converge. Calculating the force constants at the final geometry shows multiple negative frequencies, the...

02 February 2017 1,971 5 View

How to calculate the interaction energy from different types of interactions (pi-pi stacking, dipole-pi interaction)?

I have a system containing two aromatic molecules. One of them contains a functional group with a lone pair. I want to calculate the interaction energy in details. I used PSI4 to perform SAPT2+...

02 February 2017 6,637 4 View

How to determine the formation constant of a metal ion complex considering the effect of the solvation sphere explicitly?

I am trying to calculate the free energy of formation of Ferrous-phenanthroline 1:1 complex in water using Gaussian 09. I need to consider solvation of Ferrous ion explicitly and have calculated...

02 February 2017 9,133 3 View

How to calculate MM charges for a biomacromolecule?

I optimized a biomacromolecule with UFF method, then used IOp and pop=esp keywords for calculate biomacromolecule partial charges, these charges as QEq charges were calculated in .log file. But...

02 February 2017 7,016 5 View

What should be better suitable functional/basis sets for optical properties calculation of the compounds with zinc atoms or any transition metals ?

Calculation in Gaussian 09 only. Some one please suggest. Thank You..

29 January 2017 5,967 8 View

How do I choose an initial value for the parameter??

Choosing the initial values of a parameter at beginning of procedure like estimation of parameters is crucial. AS far as I know, good starting point leads to fast converging, for example, the good...

28 January 2017 3,468 2 View

My IRC calculation ends with a message: ... Delta-x Convergence NOT Met Maximum number of corrector steps exceded ... How should I change input file?

I try to do IRC calculations in Gaussian09. The calculations end with error termination and in the end of .log file, there is a message: WARNING: Bulirsch-Stoer Method is not Converging CORRECTOR...

26 January 2017 9,835 13 View

Why does my transition state have no imaginary frequency?

Dear experts, I performed a transition state calculation. First I scan the specific bond and then use Berny opt to guess the transition states. However , after optimize, the output of Berny looks...

24 January 2017 6,972 11 View

What information can we get from ADMP calculation using Gaussian 09W?

What information can we get from ADMP calculation using Gaussian 09W? There are trajectories and times in fs data. What can we resolve from those data?

23 January 2017 8,533 1 View

No negative frequency found but no stationary point found after freq check using Gaussian?

Using the following punch line: # OPT=(Tight) freq b3lyp/6-31g(d) Int=(Grid=Ultrafine) CPHF=(Grid=Fine) Guess=save geom=connectivity I reach a stationary point: Maximum Force 0.000000 0.000015 YES...

22 January 2017 6,329 5 View

How to perform an MPWB1K calculation with Gaussian 09?

MPWB1K is recommended for saddle point geometries and available in Gaussian09 Revision A.01 and later. But I couldn't get appropriate keywords /or IOP to run MPWB1K with Gaussian 09 Rev. B.01....

14 January 2017 4,897 4 View

Can anyone help me with some open source softwares which are capable of CCSD method to be applied in computational and theoretical chemstry?

Computational chemistry, quantum chemical computations

04 January 2017 661 14 View

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