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Re: [Phys-L] simulation of "bonding"



In my Windows 10, your (and Sherwood's) programs do NOT work in IE 11 - they DO work in EDGE.

Bob Sciamanda
Physics, Edinboro Univ of PA (Em)
treborsci@verizon.net
www.sciamanda.com

-----Original Message----- From: Robert Cohen
Sent: Sunday, March 06, 2016 9:06 AM
To: Phys-L@Phys-L.org
Subject: Re: [Phys-L] simulation of "bonding"

A couple more comments:

1. The programs don't display correctly in Explorer or Edge, as far as I can tell.

2. I added the values of the electric PE and the KE's of the pair and the environment. The values are scaled by the difference in the initial and minimum PE's.

3. I created a new program where there is some initial movement in the particles (with the listed KE values being relative to the initial KE values).

Compare:
<http://www.glowscript.org/#/user/rcohenpa/folder/Public/program/chargeinteractions2>
With:
<http://www.glowscript.org/#/user/rcohenpa/folder/Public/program/chargeinteractions>

4. The electric force is 1/r because the region is 2-D. Consequently, the PE is ln(r). I don't think this makes a difference but I could do the F as 1/r^2 if anyone thinks that is a problem.

5. I notice that there is a slight trend toward higher total energy values, which I assume is due to the numerical technique but I'm not sure about that.

________________________________________
From: Phys-l [phys-l-bounces@www.phys-l.org] on behalf of John Denker [jsd@av8n.com]
Sent: Saturday, March 05, 2016 9:59 PM
To: Phys-L@Phys-L.org
Subject: Re: [Phys-L] simulation of "bonding"

On 03/05/2016 06:58 PM, LaMontagne, Bob wrote:

I would love to hear other thoughts on this.

My thought is that the simulation looks good to me
in every detail. It makes a fine lesson.

Insofar as some people find some of the details
surprising, it makes an even better lesson.

the bonding energy is usually a fixed number.

Chemists /report/ it as a fixed number because they
habitually report the /standard/ enthalpy of formation,
i.e. formation at (roughly) STP.

If you care about the /actual/ (as opposed to standard)
enthalpy of formation, it is undoubtedly temperature
dependent, and this is nicely reflected in the simulation.
The newly-formed pair appears to be in a vibrationally
excited state (or the non-QM analog thereof) appropriate
to the final temperature. This looks kosher to me.

If somebody sees something wrong or dubious, please
explain in greater detail what you are seeing, and
why it doesn't seem right.

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