Does anyone know of a proof, that the divergence of a vector field exists?

More Roger Hawksworth's questions See All

What Is the Definition Of The First Order Electric Field Correlation Function For A Vector Valued E?

I have not found an explicit definition, as far as I know, of the first order correlation function for a vector valued electric field. What I have found is a definition that works for a single...

06 July 2017 7,964 1 View

What is the best way to handle the ‘grad div E’ term?

I have tried to derive, in a particular form, an equation for the electric field of light propagating in a dielectric. Unfortunately, for my intended purpose, for the case of electromagnetic wave...

31 December 2016 1,979 8 View

Does anyone have the algebra for transforming grad?

I want to transform grad from Cartesian coordinates to spherical polar. Could anyone provide the details for this? I would also like to be able to transform grad to any coordinate system, even...

05 June 2016 8,208 5 View

What is the most direct way to measure the helicity of a photon?

I have an interest in quantum optics and have been studying the electromagnetic field, photons and related material. I wondered what the most direct method of measuring the helicity of a photon...

01 January 1970 2,689 2 View

How to calculate CCS for Sodiated adduct ions and Multiply Charged Ions?

I'm currently working on calculating the collision cross section (CCS) for various ions, and I'm facing challenges when dealing with sodiated and multiply charged ions. Most of the resources I’ve...

08 August 2024 8,329 0 View

1. If I can quantize the atom using this hyperbolic spiral and classical physics, could nature do the same?

If we map as a continuous motion an ionising electron (beginning its journey at n=1) in an H atom, a specific hyperbolic spiral appears (see animation). When we solve this spiral formula, we find...

07 August 2024 5,343 2 View

How are iso-frequency contours plotted?

Let's say we have a standard, regular hexagonal honeycomb with a 3-arm primitive unit cell (something like the figure attached; the figure is only representative and not drawn to scale). The...

07 August 2024 1,937 1 View

Inquiry on Maximum Nucleic Acid Volume for 2.5 mL Liposome Solution?

I am currently working on a project involving liposomes and need to determine the maximum volume of siRNA that can be added to a 2.5 mL liposome solution with a total lipid concentration of 10...

30 July 2024 6,420 1 View

What is the best method to detect the chemical composition of pollen ?

I have multiple small samples of grass pollen with anthers. I want to find a method to identify concentrations of proteins, lipids, and other various elements for these samples. any suggestions?

28 July 2024 5,331 1 View

How can I use DFT-D3 correction ( Siesta version 5.0.1)?

Dear Siesta Users, I installed Siesta 5.0.1 and I want to use Grimme's D3 correction. According to the 5.0.1 manual, I could use a few parameters to include the D3 correction in the...

27 July 2024 5,748 0 View

EDC carbodiimide and NHS easter 's half life among different pH?

It has been long known that EDC carbodiimide and NHS easter's half life agains hydrolysis are highly related to pH. However, very surprisingly, not yet found a paper giving a table/chart of their...

25 July 2024 8,738 0 View

Is the zero-zero component of the metric tensor equal to 1 for accelerating reference frames?

Consider the case of negligible gravity but there is an accelerating reference frame. Its origin traces out a trajectory, or world line, seen in some inertial reference frame. The Lorentz metric...

24 July 2024 1,608 15 View

Mechanochemistry: ball to powder mass or ball to powder volume?

I run mechanochemical reactions that involves the use of a large amount of catalyst (1:1 molar ratio to the reactant). When I try to understand the effect of amount of catalyst on the reaction, I...

23 July 2024 9,938 1 View

How to eliminate the carry-over effect in GC-MS/MS system?

Hi, I am a PhD student working at Jagiellonian University, Faculty of Chemistry. My work is related to the development of new analytical methods for the quantification of short-chain fatty acids...

22 July 2024 5,492 6 View

William Mullin

You will find a thorough proof in the book "Div, Grad, Curl and All That" by H. M Schey, W. W. Norton

Jacques Lavau

There is at least an inferior horizon limiting the validity and competence of the scholar geometry we were taught. Unlimited extrapolation from our macroscopic habits into the microphysics domain has never been validated.