33 Questions 62 Answers 0 Followers
Questions related from Muhammad Khattab
I am a beginner and I found some tutorials on GROMACS website. Although I was able to follow some of steps through typing commands in ssh window, but I wasn't successful to run energy...
12 March 2021 5,692 2 View
For the best of my knowledge, the absorption (excitation) energies calculations (using Gaussian) are performed on outer shell electrons therefore we obtain "simulated UV-Vis spectrum". But I need...
02 October 2020 680 3 View
I am wondering how to draw ferrocene molecule in Gaussview, should iron atom be hanged between two five-membered ring with no covalent bonds projecting from iron atom? or I should draw bonds? if i...
16 September 2020 3,403 6 View
Tutorial currently available on the website is backdated to 2014, I need to find a recent tutorials (videos) for 2019 versions because the MOE has been developed progressively in the last few years.
28 April 2020 1,437 6 View
The adsorption energy between 45 atoms molecule and 10x10 unit cell of graphene needed to be calculated. The potential energy surface is very shallow and i can't reach a minimum structure. Any...
08 August 2019 9,918 6 View
I'm wondering how i can find an updated list of FDA-approved drugs for example, proton pump inhibitors, Topoisomerase inhibitors or whatever category.
30 May 2018 406 5 View
As per "Exploring Chemistry with Electronic Structure Methods" 3rd Edition book, R.E.D tool are used to calculate MM charges http://upjv.q4md-forcefieldtools.org/RED/ However the download link is...
10 November 2017 9,540 4 View
From scientific point of view, if a h-bond is formed as in RN-H.....NAr The covalently bound proton can transfer to other side forming RN.....HN+Ar if it can take place, is there a reference for...
17 August 2017 1,257 5 View
I noticed when I adjust the pH of chromophore solution containing surfactant (triton X100) for example at pH=3 using HCl, it gave me absorption and emission spectra which are completely different...
27 March 2017 3,400 3 View
if one needs to study the effect of acid or base on the absorption and fluorescence spectra, should a buffer solution be used? or it's enough to add for example 1 uL of acid or base to solution...
24 March 2017 7,572 3 View
In pubchem, i found the pKa of DMF is -0.3. However it is a strong base, which means its pKa value should be high (>16).
18 March 2017 8,776 9 View
I expected occurrence of two isomers populated at 3% and 97%, but it seems i used diluted sample. can u advise which concn. is suitable for 1D and 2D NMR measurement. I noticed in HNMR and CNMR...
01 February 2017 1,876 2 View
I noticed at low temperature (0-20) C, water condensation on cuvette walls takes place resulting in false results. Please advise how to solve this problem.
16 December 2016 8,324 6 View
i have a list of vendors who sell bosutinib isomer mistakenly, but i don't know where to buy the correct one.
20 October 2016 9,650 3 View
I am so confused, there is a huge discrepancy in DM values got from these two software. e.g. DM= 8.08 D using gaussiew while 32.83 D using Avogadro.
14 July 2016 3,160 6 View
what are the suggested possibilities and how to test it.
26 May 2016 6,893 1 View
For instance, i need to know how much water left in ppm after drying ethylacetate with molecular sieve 3 A.
24 May 2016 1,655 3 View
From your experience, what i the best basis set for a small molecule 33 atoms containing (S, F, N). The goal is to measure vertical excitation. Regards, Muhammad
29 April 2016 1,962 5 View
I am a gaussian beginner and i am not sure about what should be done for this job. 1- Should I draw a water molecule near to the site of proposed intermolecular H-bonding with the studied...
17 March 2016 1,806 9 View
Dear all, the problem is m2 is negative and also m1 has bigger value than m2 (positive), therefore i got a negative dipole moment for the ground state. and i can't calculate the ES dipole moment...
14 February 2016 2,069 2 View
The studied compound showed dual emission which maybe due to ESIPT. how i can prove formation of ESIPT.
22 December 2015 6,067 4 View
If the value is higher than certain range, should only one quenching mechanism present? i appreciate if you could send me references for that. Regards, Muhammad
10 December 2015 3,462 2 View
I need to plot excitation (x-axis), emission (y-axis) and Intensity (z-axis). I am confused because for every excitation wavelength, there is a certain intensity and the same for emission. Which...
25 November 2015 6,421 5 View
The compound under study exhibits large stokes shift in polar and nonpolar solvents ranging from 90:170 nm. what are all rationale for this large shift? e.g. - excited state intramolecular...
23 November 2015 5,628 15 View
What is the meaning and explanation of finding irregular absorbance in UV-Vis spectrum. Actulayy i have 2 overlapping absorption bands at 330 and 340 nm, but i don't know why i got irregular...
30 August 2015 9,543 7 View
I mean how to know of this vibration is scissoring or wagging or twisting, ........ and what is meant by scaling and how to do it.
02 April 2015 1,380 10 View
I am using Gaussview to create my input files, but i need to know how to freeze a bond. Is it by Gaussview? and how? Does freezing means freezing the bond length or rotation, or both?!
19 March 2015 1,458 9 View
Are there some interactions happening, or do these solvents decompose into HCl?
16 March 2015 6,717 4 View
I calculated AUC of emission spectrum and i was asked to calculate the corrected AUC. i don't know why and how.
07 March 2015 7,930 1 View
I already got a reference stating the values of most solvents, but not including glycerol and N-methylformamide. I'd appreciate if you could help in this matter.
02 March 2015 1,870 10 View
In literature, sometimes I find Chloroform, CCl4 and DCM classified as Polar aprotic and sometimes as non-polar. I am totally confused. Is there international approved classification of solvents...
02 February 2015 6,311 3 View
I need its value to be substituted in the Lippert-mataga plot to calculate the difference of dipole moments between excited state and ground state.
20 January 2015 2,568 2 View
The reaction mixture is poured onto water, but it is still remained sulfur salts. Positive sulfur test for benzimidazole containing no incorporated sulfur. And SO2 and SO3 fragments appeared in...
04 December 2013 2,244 9 View
