Does Heisenberg's Uncertainty Principle use generalized momentum or kinetic momentum? If it uses kinetic momentum, then what do we do in case of a photon as mass is zero so $\frac{h}{4 \pi m}$ is undefined. If it uses generalized momentum how do we write: \begin{align} px &\leq \frac{h}{4\pi}& \...

1. Some sources state that physical rotation of monoatomic molecules or rotation about the internuclear axis of a linear polyatomic molecule are non-physical (because of symmetry) and are therefore not considered rotations when counting the number of rotational degrees of freedom. Other sources s...

For instance, consider a system with $p_x$ and $p_z$ orbitals at the vertices of a square (on xy-plane). A square by itself would have $D_4$ symmetry. However, because of the $p_x$ orbital; the $90^\circ$ rotation ($C_4$) and $270^\circ$ rotation ($C_4^{-1}$) are no longer symmetry operations. No...

if the nth period were to end with the filling of the last sub shell of the nth shell then find the no of elements in 4 rd period

Radial Distribution Function $(4πr^2R^2(r))$ gives the probability of the electron being present at a distance $r$ from the nucleus. Answer: The given statement is correct. My Query: According to me, isn't the Radial Probability Distribution Function ($RPDF$) used for finding the probability of...

When I change c lattice parameter and optimize the structure with DFT-D, every time I get a significantly different geometry with different energy? Why is this happening with DFT-D?

Let's say you have three or more different geometry files (xyz) for the same structure and you want to compare them. What would be best way for that?

I have made e test with PBE; I used two different input geometries for the same structure and I got two different optimized geometry c lattice parameter difference = 0.06 Angstrom total energy difference = 0.0005 eV

I would like to generate a Z-matrix from the following XYZ file (C2H6dimer.xyz): 16 C2H6dimer C 0.539202 -0.539202 1.933833 C -0.539202 0.539202 1.933833 H 1.536064 -0.098299 1.932264 H 0.459532 -1.174264 2.816008 H 0.456405 -1.179449 1.055941 H -1.536064...

I am confused about how to calculate the bond lengths within a given structure given its .cif file. I have highlighted the bond of interest in the image below. The atom coordinates are shown in the dialog box at the bottom of the screen. I used the formula for calculation of distance between two ...

I'm trying to simulate the Belousov-Zhabotinsky reaction mathematically, with a system of ODEs. I know how to do this with the Oregonator and now I'm looking for another model to simulate the BZ-reaction. The Brusselator model is often mentioned as a model to simulate an oscillating reaction and...

I just recently began to study quantum chemistry and need some clarification for the construction of Kohn-Sham orbitals. Consider a system of several atoms. Let there be $N$ electrons in this system. We can reduce the description of such a system to the $\psi_i$ single-electron wave functions de...

I have written a code in Mathematica and have obtained the final energy of the hydrogen molecule. I have used Gaussian basis functions for this calculation. Now I need to plot the ground state wave function. How can I do so? I just know that the ground state wave function is defined as \begin{ali...

I have the following system of reactions: $$ \begin{aligned} \ce{X_1 + Y_1 &<=>[$k_{21}$][$k_{12}$] X_2} \\ \ce{X_2 &<=>[$k_{32}$][$k_{23}$] X_3} \\ \ce{X_3 &<=>[$k_{13}$][$k_{31}$] X_1 + Y_2} \\ \ce{X_2 + Y_3 &<=>[$k_{42}$][$k_{24}$] X_4} \\ \ce{X_4 &<=>[$k_{34}$][$k_{43}$] X_3...

Python module RDKit is great, but it cannot be installed by pip, and therefore it is difficult to use it sometimes in a virtual environment. I am wondering that if there are some alternative python modules that can convert smiles to chemical structures?

Ovality gives a measure of how the shape of a molecule approaches a sphere (at one extreme) or a cigar shape (at the other). Ovality is described by a ratio of volume to area (see https://en.wikipedia.org/wiki/Ovality). So, it is basically "just" about intersecting Van-der-Waals spheres. Although...

I am looking for a free software able to draw 3d micelle configuration like the figure attached.

I want to output a molecular orbital diagram. Can anyone recommend a software to do this? Also I searched for a python module, but didn't found a pure solution. Maybe I am using the wrong keywords. I want to connect two atoms with a specific electron configuration, to see at which energy levels t...

The Gibbs–Helmholtz equation was developed in the 1870's, while Nernst's heat theorem was developed in the early $20^{th}$ century (according to google/wikipedia). Nernst's heat theorem tells us that the change in entropy tends to be zero in absolute temperature. But did Nernst's heat theorem pro...

Calculate $Δ_\mathrm{r}G^\circ$ for the following reaction: $$\ce{2 CH3OH(l) + 3 O2(g) -> 2 CO2(g) + 4 H2O(l)}$$ using $Δ_\mathrm{r}H^\circ$ and $Δ_\mathrm{r}S^\circ$ at $\pu{298.13 K}$ $(\pu{25 °C}).$ The values for $Δ_\mathrm{f}H^\circ$ and $Δ_\mathrm{f}S^\circ$ can be found in Appendix G of t...

I'm trying to make sense of the derivation of the equation $$\Delta G = \Delta G^0_r + RT\ln(Q)$$ While searching for a derivation of this equation that made sense to me I came across a publication in the Journal of Chemical Education that suggests it is incorrectly applied if not completely wro...

Heat liberated by a given amount of an ideal gas is $\pu{1200 cal}$ at $\pu{300K}$. What is the Gibbs free energy change for the gas in this process? My attempt: I know that for a reversible process the net Gibbs energy change of the system + surrounding will be zero. But I have no idea how ...

While providing the reason for the higher melting point of trans molecules, everyone says that trans molecules are more symmetric than cis molecules. An example can be found over here, where the OP states that: trans-2-Butene has more symmetry than its cis isomer which results in better packing ...

I am following the video lectures by Neeraj Saini sir and in this video$^{\dagger}$ he said that $\ce{CO2}$ has infinite planes of symmetry. But I think that if we take into account the orientation of $π$ bonds (which I don't know if we have to or not) then $\ce {CO2}$ molecule must have $2$ pla...

Why do most character tables (e.g. $C_{3h}$ but not $C_{2h}$) include an $(x^2 + y^2)$ term? Is it an abbreviated form for $d_{z^2}$, applying only where $3d$ (and higher) orbitals might be involved, or just a generic binomial term with no specific relevance? The only clue I can find is on this p...

From what I understand, the symmetry number for a molecule can be defined in 2 ways: 1. The quantum mechanical symmetry number corrects for overcounting the number of possible rotational states of a rotating molecule. Here's a source using this method. 2. The classical symmetry number corrects fo...

I've been performing Gaussian 16 DFT optimization and single-point energy calculations on different conformers of a rather large organic molecule. My first series of calculations was without solvent model, the second one was with dichloromethane solvent effects included via SMD model. When I anal...

Why is it so difficult to perform DFT calculations that consider temperature? I have seen that time-dependent DFT is needed to model systems at high temperature. Why is this the case? What about finite temperature functionals? Why is it also acceptable to use zero-temperature functional with TD...

I was trying to write a name for a synthetic molecule in QM9 dataset. The molecule is: is 3-aminooxolane-2-carbonitrile a correct name for this?

I'm new to SMILES strings, and have noticed that they're not standardised. Firstly, what is the reason for different structures of SMILES strings to represent the same compound? Why not have a standardised format? Secondly, are there any tools to convert between different SMILES strings for a gi...

According to the book Machine Learning Meets Quantum Physics QM9 is built up from $\sim 134 \mathrm{k}$ drug-like molecules with up to nine heavy atoms (C, N, O, or F). I'm assuming that drug-like molecule is referring to Lipinski's rule of five. I used RDKit to plot 2D histogram of octanol-wat...

If an atomic orbital were holding 2 electrons (its maximum capacity), then how many electron clouds would there be? Thanks for your answers in advance.

If an atomic orbital consisted of 2 electrons (its maximum capacity), how many electron clouds would there be? I think its 2 electron clouds, one for each electron but I'd love some confirmation.

Question: According to Bohr's atomic model, is the following graph correct? Answer: Yes, it is correct. My Approach: According to Bohr's Model, the total energy of an electron in the $n^{th}$ shell of an uni-electronic atom having atomic number = $Z$ is $$TE=-13.6\frac{Z^2}{\:n^2} eV$$ And its p...

Let me know how to calculate the atom economy for the first reaction. I am attaching my attempt.

I was wondering how one can define the axes for a molecule with several equal axes of rotation, all of which pass through the same atom. I know that the $z$-axis is usually defined as the principal axis, or the axis passing through the most atoms if none are equal. But in the case of, say, the $D...

I came across a question asking which of the following conversion/reductions can be accomplished using ammoniated electrons. $\ce{O2}$ to $\ce{O2^{2-}}$ $\ce{K2[Ni(CN)4]}$ to $\ce{K4[Ni(CN)4]}$ Aromatic ring Non-terminal alkyne I have been able to find on Wikipedia that $\ce{O2}$ is reduced t...

I am trying to understand the symmetry elements of space group number 194 (P$6_3$/mmc), which is hexagonal and has 24 symmetry operations. In the table of symmetry operations it says that it has three glide planes, which I marked in the figure (see blue rectangles). However, more than three gli...

I was learning about crystal field theory recently. I am quite confused about predicting the shape of $\ce{[Cr(NO)4]}$ complex because I am not able to conclude whether it will be square planar or tetrahedral. How to predict the shape of $\ce{[Cr(NO)4]}$ using crystal field theory? Will $\ce{NO...

The ligands $\ce{PPh3}$ and dppe (dppe = 1,2-Bis(diphenylphosphino)ethane) are both strong field ligands, but is one obviously a stronger field ligand than the other or are they roughly equal? The reason why I ask this question as I am researching into $\ce{[NiCl2(PPh3)2]}$ and $\ce{[NiCl2(dppe)...

I have $\ce{[ML6]}$ & $\ce{[MD6]}$ as two complexes. I know the $\Delta_0$ & hybridisation of each of them. How do I calculate the CFSE for $\ce{[ML4D2]}$ ? This is my way of thinking : I can calculate the CFSE of $\ce{[ML6]}$ & $\ce{[MD6]}$ in terms of Pairing Energy and then do some manipulatio...

I'm stuck in a question that says CuFe$_2$O$_4$ has inverse spinel structure but ZnFe$_2$O$_4$ has normal spinel structure. Explain. Now I know that normal spinels have a structure like (A$^{II}$)$^{tet}$(B$^{III})^{oct}_2 O_4$ like structure while inverse spinels have a $(B^{III})^{tet} (A^{II...

I'm really struggling with finding the magnetic moment of this complex: In the solutions, it says that it is 2.83 BM (which corresponds to 2 unpaired electrons). However, in drawing out the d orbital diagram (using crystal field theory) I found that there are actually 4 unpaired electrons (since...

I'm trying to do Normal Mode Analysis for my MD trajectory. I'm following Amber tutorial (http://ambermd.org/tutorials/advanced/tutorial3/py_script/section5.htm) which uses an example of estrogen receptor protein and raloxifene ligand. Since I'm only getting errors from this, I'm having a couple ...

First consider a simple polymer, like polyacetylene: Its torsional barrier can be determined by DFT calculations by considering "enough" units and performing a simple dihedral scan. "Enough" appears to be 5-7 units (J. Chem. Phys., 2014, 140, 054310) But now I want to study a more complex pol...

Disclaimer: this question is related to my previous question, although it is much more detailed Consider the following rotation of butadiene: I want to determine the relative energy of each dihedral angle by molecular dynamics (MD). My initial idea was to simulate butadiene in the NVT ensemb...

I have a curiosity to know how long it will take for a water molecule to move a certain distance in pure water. I can put it simply as how much time for a water molecule to travel the whole length of a typical glass of water if no collective motion is present (therefore very still water with no c...

I'm reading p.1238 of Mcquarrie's Physical Chemistry: A Molecular Approach textbook. In the last line of the page, the author explains that the value of the reaction cross section in the constant total energy depends strongly on the vibrational state of the reactant. Of course, it means that not ...

I've read at many places that temperature is the average kinetic energy of particles present in an object. I just don't intuitively get how kinetic energy is connected with temperature. And how is heat connected with temperature then? Then what exactly is temperature? All of the descriptions give...

I'll derive the pressure of a system of particles, which would be used in a MD simulation for example, according to Allen's Computer Simulation of Liquids and show where my issue is. Consider a Hamiltonian system with $N$ interacting particles and generalized coordinates $q_k$. The virial theore...

For a closed system at fixed N,V,T there is a solid in equilibrium with its vapor. I'm told that I can minimize the helmholtz free energy to find that the equilibrium condition is given by $N_g = \frac{q_g}{q_s} $ Where $N_g$ is the Number of particles in the gas phase, and $q_s$ and $q_g$ are t...

Consider the following unimolecular reaction: $$\ce{H2O2 + M -> OH + OH + M}$$ The high pressure limit unimolecular rate coefficient for this reaction is $k_\mathrm{uni} = A\cdot \mathrm{e}^{\frac{-E_\mathrm{a}}{R \cdot T}}$, where $A = \pu{3E14 1/s}$, and $E_\mathrm{a} = \pu{305 kJ/mol...

I'm trying to migrate away from Gaussian 09, using Gamess-US instead for molecular modelling of some heavy alkaline earth metal complexes, using density functional theory (DFT). In some of my previous Gaussian inputs I used the SDD (Stuttgart/Dresden) pseudopotential with the metallic cation ($\c...

I have some calculations results I runned previously using Pople's basis sets, mostly 6-311+G(d), under Gaussian09. These days I read some texts on Frank Jensen's family of polarization consistent, segmented basis sets, optimized for DFT (pcseg-0, pcseg-1, pcseg-2, pcseg-3, pcseg-4 and the respec...

As a example, If I have a square planar complex of a cation with both a weakly polar ligand (X) and strongly polar ones, like ammonia and water I expect a bit of stabilization due to formation of a hydrogen bond between ammonia and water, if they are in adjacent positions: NH3 │ X─ M² ─OH2...

Actually, I'd like to compute decay rate using : $$ \Gamma = 2\pi \ | \langle ab|V|cd \rangle|^2 \delta\ (\epsilon_f-\epsilon_i) $$ where a, b, c, d are the MOs and V is coulomb interaction, and $\epsilon_f$ and $\epsilon_i$ are final and initial energy of the system. I am interested in comput...

I am trying to perform optimisation of the molecule attached. I need to get partial charges and frequencies. The issue is that it doesn't converge with following input: %nprocshared=8 %mem=16GB %chk=CTB.chk #n opt b3lyp/gen pop=(ReadRadii, savechelpg) SCF=QC CTB 0 2 Ce -6.41954 5.21611 0.61820 ....

I'm trying to understand the QM datasets (QM7, QM8, QM9), however, in the description of QM7 the data is described as follows: [The] QM7 dataset, which is a subset of GDB-13 (a database of nearly 1 billion stable and synthetically accessible organic molecules) containing up to 7 heavy atoms C...

Is there a database or API(rest calls) for verifying chemical equations? Example, Na + Cl -> NaCl + Loss of energy. So if I want to verify if there is a loss of energy or gain of energy? Is there any online portal where I can write a chemical equation like above and verify whether its correct o...

I'm looking for a fluorophore with exceptionally long lifetime to use in an oxygen optode (the longer the lifetime the less timing precision needed in the electronics). So far the longest I have encountered in my searches is 600nS for Ru(bpy)3[PF6]2 found in this table but that resource appears ...

I am currently working on a machine learning project, in which I need access to many IR spectra, the more the better, in order to build a classifier that will used some unsupervised learning in order to work out the functional groups present in the IR Spectrum. The only databases I have found so ...

I am trying to write a program that will be able to read CIF files. I am testing on a CIF file like this: _symmetry_space_group_name_H-M 'P 21/c' _symmetry_Int_Tables_number 14 loop_ _symmetry_equiv_pos_site_id _symmetry_equiv_pos_as_xyz 1 x,y,z 2 -x,1/2+y,1/2-z 3 -x,-y,-z 4 x,-1/2-y...

It's common to read statements like one given below on PubChem: Conformer generation is disallowed since MMFF94s unsupported element. What's the meaning of the statement, and why are certain compounds unsupported? And what is MMFF94s? This might be something really basic, but since I have n...

I have a project where I'm trying to program my own force field, and I decided to use the AMBER gaff2.dat force field parameters. However, I am really struggling parsing the gaff2.dat file when it is about the dihedral angle parameters. I am now trying to replicate the rotation around -O-C-C-O...

In the 3d conformation of 1,2,4,5 - benzenetetrol, how could i determine the direction to which hydrogen atoms of hydroxyl groups would point? and if there were tertiary butyl groups in positions 3 & 6 would it be more stable for hydrogen atoms to point in the direction away from t-butyl groups a...

I am recently using the GMMX add-on in gaussview to conduct conformer search. I was using the grid search method and the progrom suggested the number of structures is 729 (See picture below). I submitted the job and it completed normally. However when I checked the log file, the "Nmin" is 496 (Se...

I tried to parameterize a particular x-y-z-t dihedral angle of novel molecule using a Quantum Mechanical scan, but I got the strange result below. The energy changes sharply around 130° and $E_\text{dihedral}(0°) \neq E_{dihedral}(360°)$. I performed PES scan in gaussian09 and psi4 and I got t...

I am reading the book on MONTE CARLO METHODS IN AB INITIO QUANTUM CHEMISTRY by Hammond and Lester. (Chapter 5-Variational Trial Functions, Section 5.3-Hartree Fock and Beyond, Sub-Section 5.3.3 Hartree Fock and Correlation Energies)In section 5.3.3, the book says the following, "In Monte Carlo, ...

I am trying to balance some chemical reactions by using the Gauss' elimination method and I noticed that this method does not work if the creation of a matrix with exactly one degree of freedom is not possible. In this example $$\ce{H2O2 + NO3- + H+ → O2 + NO + H2O}$$ I succeeded in creating ...

It is a very general question. Is there a good way to systematically increase the accuracy and precision of a measuring tool using only mathematical means? For example, average 10 measurements can create a better one. Or using two independent tools. I don't know if measuring theory or statistic...

I have performed a large number of calculations in order to determine the ethanol content of wine. These included titrations using burettes, mass measurements using analytical balances, and others. I know the uncertainties of the apparatus. I am given a task to find the ethanol content of wine (...

I always thought that p-orbitals had a dumbbell shape as pictured below. (image source) However, I was reading an article (see Table 1, item 2) that says, "...the spherical $\mathrm{p_{1/2}}$ subshell..." (my emphasis). The implication being that the $\mathrm{p_{1/2}}$ orbital (subshell?) has...

I am studying the Application of perturbation theory to hydrogenic atoms subject to internal or external electromagnetic fields. The very first equation it uses is the hamiltonian of hydrogenic atoms $$H_0=\frac{p^2}{2\mu}-\frac{Ze^2}{r}$$ This equation is said to have no spin and is completely...

Also, is it possible to see frame-shortening effects on electrostatic forces/van der waals at the edges, or are molecules too weak or necessarily neutral to be manipulated this way?

I searched on Wikipedia for reactivity series but it showed me Caesium as the most reactive metal. I know and have studied that reactivity increases as we go down the first group. Then shouldn’t it be Francium more reactive than Caesium than the other way around. PS: I study in class 10 so plea...

I am confused about what seem to me two very different explanations for relativistic contraction of orbitals for heavy elements. My teacher told me that since 1s electrons in heavy elements travel very fast their momenta is much larger than predicted by classical physics. Hence the 1s orbital con...

DeepChem does not run on windows, so I am considering to try Google Colab. Is there any key feature I would be missing by using Google Colab remotely from Windows rather than the original DeepChem on Linux?

I was reading about molecular graph based generative models, which attempt to generate new molecules by training on a subset of a molecular dataset, such as QM9. In these works, there are 2 types of constraints that define the validity of the output: The sum of the order of the bonds that are i...

Let a collection of molecular graphs have at most $N$ nodes, $d$ node types (atom type), and $t$ edge types (bond types). A graph from this collection is normally represented by the tuple $(F, E)$ with \begin{equation} \text { node-label matrix } F \in \mathbb{R}^{N \times(1+d)}\quad \text { and...

I'm not sure the exact difference between the MCSCF and CASSCF methods. I know that the CASSCF method proceeds by optimizing both the CSFs and MOs (I mean the coefficients), but I don't know if this is also the case in MCSCF calculations. My guess is that in MCSCF only the coefficients of CSFs w...

Some topics here have touched on this before (see 1, 2, 3), but I haven't found a clear definition yet. I would like to know what exact property of the wave function these terms refer to. It would also be helpful to have a clear definition of 'reference' and 'configuration'. I'll try to explain...

According to the molpro manual, section 7.3: In order to compute excited states it is usually best to optimize the energy average for all states under consideration. This avoids root-flipping problems during the optimization process and yields a single set of compromise orbitals for all...

I have searched through the GAUSSIAN 16 manual and have not been able to solve these two related issues: (1) I want to be able to save the CI vector and load it as an initial guess for a different calculation. Or at least to be able to manually set the initial CI vector. (2) During a geometry o...

I have read some other posts explaining what multi-reference and multi-configuration are with regards to the wave-function (such as What exactly is meant by 'multi-configurational' and 'multireference'?). However, what does it mean for a molecule specifically to exhibit high multi-reference cha...

Recently I was shown the book "Density Functional Theory II, Relativistic and Time Dependent Extensions" by Nalewajski in which a chapter from E. K. U. Gross et al. is printed. [1] This chapter contains an interesting statement in it's introduction: Excited-state properties, however, are noto...

When I have an excited state, is there a relation between the transition density associated with this electronic transition and the density difference between the excited state density and the ground state density? Can the transition density be equal to the difference density?

I have been recently reading a lot on the quantum mechanical theory regarding Density Functional Theory, DFT, and Time Dependent Density Functional Theory, TDDFT (Oscillatory and Rotatory Strengths in particular) in order to understand how first principle calculations fundamental theory work. I ...

Experimentally, anisotropy factor is calculated by dividing the CD spectra by the absorbance spectra multiplying by a factor of 32980 (in order to get a nondimensional quantity) Theoretical calculations can be performed via TDDFT to obtain rotatory and oscillatory strengths, obtaining excitation...

I was reading up on the derivation of the values of various critical state functions( $\ce{Vc}$, $\ce{pc}$ and $\ce{Tc}$) from the Van der Waals equation (Physical Chemistry by G.W. Castellan). There, he was about to express a and b in terms of these critical state functions, when I came across t...

I was wondering whether the compressibility factor of a real gas (given by $Z = V_{\mathrm{real}}/V_{\mathrm{ideal}}$) is supposed to be measured while keeping pressure constant? I was attempting to answer the question below and got stumped at part (iii) because I had trouble finding out which wa...

So I was reading through my textbook on deviations from an ideal gas, and they had plotted a curve of experimental PV/nRT against the pressure. They talk a lot about why the volume is really smaller than what the ideal gas predicts, and so on, and thats why as the pressure increases, the devia...

I want to increase the surface tension of water by 1.2 - 2 times. How about adding one or more chemical substances to the water that can possibily increase its surface tension by the desired amount? But I don't know what chemical substances to add. Do you what chemical substances can I add?

For a van der Waals gas, isothermal compressibility is $$\kappa=\frac{V^2(V-nb)^2}{nRTV^3-2an^2(V-nb)^2}$$ If one substitutes the values of critical temperature and volume in this formula, isothermal compressibility goes to infinity. What is the physical meaning of this? Is it right to use this e...

I wrote a piece of code on RHF using Python a while back, and figured I'd extend it to also implement CNDO/2 (yes, I know it's old but I figured it'd be easier for me.) The approximated Fock matrix elements, taken from the original paper, are as follows: $$F_{\mu\mu} = U_{\mu\mu} + [(P_{AA} - ...

I did some research. Found some semiempirical methods that work even with heavy lanthanide compounds (RM1). But could not find any references to semiempirical methods compatible with the heavier members of the alkali earth group: Sr, Ba and Ra. If there is such method, does any open source / free...

One of the major features of semiempirical methods is that they significantly reduce the cost of evaluating 2-electron integrals. In general, they follow the formula for HF, but, introduce many simplifying assumptions. In HF for same spin electrons you need to calculate both coulomb and exchange...

In MNDO and its descendants (Sewart's PMx models, Austin's AM1, MNDO/d, etc.), the nonvanishing two-center two-electron "coulomb integrals" are evaluated via a classical multipole expansion in a local coordinate system, and then transformed into global coordinates via "standard rotational transfo...

I was reading a bit about this technique, Density Functional based Tight binding (DFTB). It's claimed it can provide a speed improvement of several fold when compared to plain DFT, still giving acceptable results. I downloaded one of its free implementations, the DFTB+ package, and started to wor...

A colleague of mine suggested to use TPSSh as a functional. Since I am applying Grimme's D3 dispersion correction by default, I was surprised that it wasn't implemented in the standard density functionals, cf. Gaussian Manual (Copy @ The Internet Archive). Since I might not be the only one to co...

I am trying correlate some experimental properties of a molecule to its calculated equilibrium geometry. To do so, I calculated the geometry and energy of some conformers. Now, I obtain mixed results when performing the same energetic calculation with dispersion-corrected (D3) and not corrected f...

Is there any analytical solution for the most common expression of column mass balance: $\dfrac{\partial C}{\partial t} + \left(\dfrac{1+\varepsilon}{\varepsilon}\right)\dfrac{\partial q} {\partial t} + u \dfrac{\partial C}{\partial t} \:\:=\:\: D_{\mathrm{axial}}\:\dfrac{\partial^2 C}{\partial t...

There's been ample work and media coverage on how to make a long C-C single bond. To my knowledge, the longest stable C-C bond is currently 1.704 Å, prepared by Schreiner Nature 477, 308–311 in 2011. All around us, there's considerable plastics, made from polymerizing alkenes like polyethylene. ...

Lately I've seen videos and some articles explaining drug design. I would also like to specifically cite this guy, who isn't the most credible guy in the planet, but some of the stuff in the video makes sense to some degree, and he just confused me further. Now I work on a completely different f...

I calculated a PES scan of Propylcyclohexane in gaussian. %cpu=16-31 %mem=32GB %chk=propylcyclohexan_scan_30.chk #p PM6 Opt=modredundant propylcyclohexan_scan_30 0 1 C -2.32729 0.36923 -0.26826 C -1.86086 1.79592 0.04793 C -1.42371 -0.68...

Does it also make use of covalent bonds to stick to surfaces?