studiot

I see the original course (in pdf) I referenced is still available https://www.umsl.edu/~chickosj/c365/lectureNMR2.pdf 6 pages NMR2 through NMR7 https://www.umsl.edu/~chickosj/c365/lectureNMR7.pdf Are these any good ? You presumably know enough Chemistry to understand functional groups in substances that are being analysed ?

@bangstrom What you are doing is a good example of what swansont was gently warning you about. I have already indicated that I am having trouble correctly understanding what you mean and here you are crowing about using physics terminology quite differently from everybody else. And then you have the gall look down on me when I try to clarify what you are saying, I am reporting yours replies as discussing or arguing in bad faith.

Since you are studying Physics, may I introduce you to this little book, whcih will answer all your questions and more. When working with a subject, even one I know well, I like to keep two (sorts of) books on the subject. A very basic book that explains things, including the maths, but is not too big and encyclopaedic. A treatise type book that works out all the special cases, wrinkles and details for when I need to delve deeply at a particular part of the subject. Susskind has written 3 titles covering much of Physics using of the first type of book and this is the one you need. It contains the whys and wherefores of quantum calculations, including useful tables of results, for entanglement, density matrices and compares with classical analogues, discussing the difference between quantum and classical versions.

A someone who suffers more than most from what you describe because I tend to write longer posts than most one liners, I fully sympathise. +1 Yes I have yet to find a proper answers and have posted pictures of what I see here. Nor can I tell how any of this is benefitting anyone, since the last thing I would ever do would be to buy something that pops up and interferes with something I am currently engaged in. And, of course, those with suitable ad blockers who thing everything in the garden is rosy so they will never see and therefore buy as a result of these adverts either. I would certainly hate loosing someone of your calibre over this.

This is what I mean by a derisory dismissive reply. What you understand by a dimensional constant is clearly not what I understand from the way you have already tried to use it. Here is my understanding of the meaning. I hope you will agree that miles (or any other distance) are not hours (or any other time). As every schoolboy used to be taught the distance walked is proportional to the time taken, at constant pace. He is then taught that this can be converted to an equation by introducing what is known as a constant of proportionality. Some proportional relationships are only used occasionally so the constant is just called the constant of proportionality. In the example case we use it so often that it is given a special name - the speed. In some cases the constant of proportionality is just a number because the two variables involved either have not dimensions at all or the same dimensions. But we have already agreed that variable distance is not the same as the variable time, So the constant of proportionality also performs a second duty. It 'converts' dimensions of time into dimensions of distance. In that case it can legitimately called a 'dimensional constant' and will be necessary even if the conversion is 1 hour walked converts to 1 mile covered. Note that I have used units rather than the more general dimensions, which brings us to our second point, which you clearly did not understand from you answer to my question which was to find out if we can usefully employ the standard dimensional notation. Nor did I mention " the inverse of LT". I mentioned L T-1 to the minus one which read the product of L and the inverse of T. And yes you did indeed mention the ratio of distance to time, or if you prefer the fraction distance over time. Anyway it is a remarkable and very useful fact that all the variables or quantities in Physics can be put in terms of a handful of basic ones. These are for Mechanics Mass M, Length L and Time T. We add to this Temperature (usually greek theta) , and a brightness or illumination measure for optics and a single electrical variable , formerly charge but now current density. So the dimensional constant has a suitable value to convert hours to miles or milliseconds to micrometre or whatever these are the units. It also has the dimensions to convert different types of physical variable. So speed has the dimensions of distance over time or L T-1 This makes the schoolboy equation distance = speed times time dimensionally correct since L = (L T-1) x (T)

You might like to compare with the Joule Thomson effect where cooling does take place this is a good pdf https://byjusexamprep.com/liveData/f/2021/12/joule_thomson_effect_76.pdf

A characteristic of the last thread and now this one is that you keep introducing new material and words that require a whole thread or two on their own. What exactly is a 'dimensional constant' ? And since you claim that there are other physical properties or quantities that have physical dimensions LT-1 please list them because I can't think of any. ? (LT-1 ; Are you familiar with this notation ?)

But what about them ?

I am finding this thread rather disappointing. For one thing I can't deteremine what it is about. Are we meant to be discussing Entanglement, the speed of light, action at a distance or what ? For another thing, if we are meant to be discussing entanglement it is rather distressing to be told that what happens before during and and after entanglement is irrelevant.

I really thought I was being clear. ...before and after... So before bond formation there are two electrons in separate obritals, each with two spin possibilities, making a total of four possible configurations. After the bond formation there is one orbital holding both electrons and the possible configurations reduce. And no , I do not think it is irrelevant, I think it is vitally important and demonstrates that our knowledge is not as limited as made out. It is important because the available combinations determine the probabilities.

@bangstrom Here is a question for you to think about in relation to knowable and unknowable states. Consider the formation of a covalent chemical bond : This involves the entanglement of two electrons. What are the possibilities for the states before and after the bond formation ?

Before launching ito some technical mathematics, let me ask you a question. How much do you know about matrices and complex numbers in general ? The density matrix is best studied in the first instance in connection with a very simple two state system (usually the spin states ). It can then be generalised to many pure states and what are called mixed states. Essentially the DM is a matric of real numeric coefficients with some rather special properties that applies to a system with finite number of states. It falls down for the potentially infinite count of states of Many Worlds.

I see you now have 5 posts under your belt as a new member. You will now have encountered the antispam measures, sadly necessary. I wonder if you have actually read the rules here, either about posting in general. Untested hypotheses belong in the speculations section, they are not pronouncements of authority for the main technical sections. When you read the antispam rules don't make the mistake of believing that you only have 5 posts. This applies only to the first 24 hours, after which further posts will be accepted again. In my first response I offered you some useful information linking your ideas to quantum theory I suggest you use this time to look them up. As well as Everett look up 'Something Deeply Hidden' by Professor Sean Carroll.

Then you will be able to explain the fault in my reasoning in my first response, rather than trying to change the subject.

I simply quoted your first line and noted that you contradicted yourself and then stated that this was the basis of your hypothesis. Why would I need to go further into it since you based your hypothesis on a self contradiction ?

Because this is a Science site, not a mystics convention.

I think you have read some third hand twice removed journalist's ideas. If you observe something you can know its behaviour. If you don't observe it you can't. So how can you know if its behaviour is changed ? Yes you can observe similar objects but not the ones you did not observe. Neither can you know what it would have done if you did not observe it. Secondly what do you mean by 'quanta' and 'observe' and by 'observe quanta' ? Followers of Everett reckon that this phenomenon is explained by there being only one giant wavefunction that cover the whole universe and everything in it. It is also called 'the many worlds interpretation' by journalists. It has some merit.

This is just plain wrong It should be F(t) = mdv/dt + (ve-v)dm/dt In your notation. I will be away again for a few days but will be able to develop this fully and further after Wednesday of next week.

Chemically bonded. Exactly right again. +1 I was avoiding talking about these first off because the general concept of chemical bonding has to be understood before tackling the more complicated matters such as exchemist is talking about. (Giant structures). Chemical bonds are the answer to my question "what holds molecules together", but they also hold other groupings called chemical species together as well, including our own DNA. To start with we divide chemical bonding into Primary bonds which are generally strong or very strong and conform to a few simple rules. and Secondary bonds which are mostly less strong and have a much more flexible rulebook. I am going to be away again for a few days so ask you further questions now or we can continue to develop this after Wednesday of next week.

Yes we normally think of solutions as dissolving something like salt or sugar in water or another liquid like alcohol or benzene. Salt is actually a compound sodium chloride NaCl. If I just added pure sodium to water the reaction is so violent it could catch fire. this is a good video; sorry I don't know how to skip the ad at the beginning. Have you had any thoughts as to why the elements in a molecule stay together ? In other words what holds the molecule together ?

Absolutely spot on. +1 Without getting too technical, here is a little bit extra. Both Compounds and Molecules have a fixed formula which means that the elements always have the same numbers attached. So ethane - C2H6 - is a different compound from propane - C3H8 , although both have the same proportions between the carbon and the hydrogen - Cn H2n+2 The next step up is called a mixture or a solution, where two or more compounds can appear in basically any proportion.

It seems to me that the current discussion is going round and round in circles, probably due to not fully appreciating the underlying Physics and Maths. There are several rocket equations, depending upon the circumstances, both concerning the rocket, its surroundings and what you want to know about it. It is not a good idea to mix up these circumstances. There are also several possible routes to solving the problem. Mathematically any equation that can be presented (and solved) as a differential equation can also be presented and solved as an integral equation. Some treatments do it this way and use what is known as an impulse. It would be very helpful if you could describe your interest further so that we can determine the appropriate response. Are you primarily in the Physics or the Applied Maths ? If we go right back to basics, the rocket problem is a sub class of the dynamics of variable mass systems, both for loosing mass (as in the rocket) or gaining mass (as in the raindrop) or even a bit of both. A general equation can be derived for all these circumstances, and appropriate values put in for each sub class. The systems described are described under Galilean/Newtonian relativity, not Einstinian relativity. As such the common variable linking the parts of the problem together is time. Differentiation is performed with respect to time. (use t) The problem is set up considering the chages to the variables during a period from t to (t+δt) and the solution found by multiplying out the algebra, discarding the product of small quantities as negilgible and finally taking the limit as δt tends to zero.

Since you and Mordred are ploughing on with the advanced stuff here are some simple notes about scalars vectors and tensors. Again I sugest yoy print the attachment out and keep it for future reference. Sorry it's all words this time but the best introduction I know without using the Einstein summation notation.All the essential features are there. First a couple of notes of my own. All vectors are linear. Mostly when a physicist says vector he means a 'directed line segment' or a 'signed line segment.' note in maths a line is a straight line that goes on to infinity or forever in both directions. That is it has no ends. A 'straight line with ends ' is called a line segment. A 'curved line' is called a curve and a piece of that curved is called a curved segment or a segment of the curve. In my previous sketch about -1 + 4 = 5 I have shown three line segments. One property of any segement, is that it has length. So if I add two segments that each have a length the result is a longer segment of length equal to the sum of both individual lengths. This form of addition is different from the rules for adding signed numbers. This is why you have to consider the meaning of the sign as well as the magnitude (length in this case). @Mordred Thie following is from Physics in the Chemical Industry by R C L Bosworth - Macmillan. A no nonsense guide as it says.

Since you are discussing vector based quantum mechanics with mordred you will find this page invaluable. You should print it out for reference. Note how simple they are.

Diagrams, Diagrams, Diagrams. Does this sketch help ?