1,701 reputation
619
bio website eutactic.wordpress.com
location Australia
age 28
visits member for 3 years, 5 months
seen May 17 at 1:08

grad student, computational quantum chemistry

Interests include chemistry, high performance computing, graphics, art, typesetting, programming (python, Java, C#, XAML)


Apr
27
comment Why does the metastable form of Technetium-95 have a longer half-life than its most stable state?
@ManishEarth, BenNorris - I respectfully submit that nuclear isomerism is far more nuclear physics than chemistry, taking place on energy and length scales orders of magnitude removed from chemical processes and not involving electronic structure. I've only ever seen it discussed in chemistry in the context of understanding Mössbauer spectroscopy. Whilst I apologise for being a bit presumptuous, I do think this question would attract a greater breadth and depth of answers on the physics site.
Apr
26
comment Why does the metastable form of Technetium-95 have a longer half-life than its most stable state?
Hopefully a moderator can shift this to phys.SE. Just surfing around tables of isotopes does however reveal that isomers that are longer-lived than their ground states are not uncommon (102mTc, 116mCs, etc.). Anyhow, this looks like another application of the difference between thermodynamic and kinetic stability. Intuitively, the decay pathways that lead to rapid decay of a ground-state isotope are less probable (maybe totally impossible) in an isomer. The isomer, whilst less thermodynamically stable, is stuck in a potential energy rut that it can only escape through slow processes.
Jan
26
comment Have we managed to make a perfect vacuum?
@Hurricane - Antimatter can be stored in a Penning trap.
Jan
18
comment Do the energy levels of electron orbitals change relativistically?
Broadening of spectral lines occurs due to the Doppler effect (as well as a number of other effects) even in non-relativistic regimes. Otherwise emission and absorption spectra would be infinitely sharp. As a side note, you may be interested to know that relativistic mass increase becomes significant for bound electrons around about the second row of transition metals and quantum chemical calculations need to take it into account for accurate energy calculations.
Jan
16
comment How can two seas not mix?
@EmilioPisanty - It seems that Wikipedia has a page dedicated to the topic. Also, Atkins Physical Chemistry 3e pp. 632-634 talks about colloid stability.
Jan
5
comment Temperature below absolute zero?
Honest question - why is this in the news all of a sudden? I was under the impression negative absolute temperature was a fairly pedestrian phenomenon.
Jan
5
comment Is there something special in the visible part of electromagnetic spectrum?
I did rather drift off course, but I guess my point is that the visible part of the spectrum is only special for life due to its energy regime (and as you noted, that there's a high flux in the visible region from the sun). Its time-dependent bandwidth is irrelevant due to biological signalling being many many orders of magnitude slower. Time-independent bandwidth (i.e. this fruit is under/overripe due to its colour) is I believe a function of how many different photoreceptors we have and how specific they are. Most humans have 3, and are able to distinguish a wide range of colours.
Dec
26
comment Calculating the speed of an object moving relative to another moving Object (Frame of reference)
This question doesn't really evince much research effort. Have you familiarised yourself with the Lorentz factor?
Dec
14
comment How do electrons jump orbitals?
Beta decay is a nuclear process (specifically a weak process), rather than a chemical one. This said, orbital transitions can occur in inverse beta decay (which is to say, electron capture) however this is only a side effect of an unoccupied core orbital being generated.
Dec
7
comment Why cant one see tidal effects in a glass of water?
You've just concatenated Alex and FrenchKheldar's answers.
Dec
4
comment Is there record of a bosonic Stern-Gerlach measurement?
Weeeeeird, I was thinking of this exact question only a few hours ago. For what it's worth, this discussion on Physics Forums draws an interesting parallel between Stern-Gerlach and birefringence.
Jul
25
comment Is it feasible for an unmanned vehicle to travel from outside the atmosphere of one planet to another without additional propulsion?
@Everyone - Yes, but space missions are planned with interactions with other bodies in mind. Also bear in mind that the vehicle is possibly going to be in some kind of orbit around the sun.
Jul
13
comment Naive Question About Batteries
@mwengler - Point taken, however this polarisation is insufficient to hold a paperclip against gravity. If I recall correctly, the potential differences involved in everyday static cling are on the order of kilovolts. I guess my comment is irrelevant as even if the paperclip were charged it would be neutralised as soon as it came into contact with the battery.
Jul
13
comment Naive Question About Batteries
Your paperclip is electrically neutral.
Jul
5
comment The Large Hadron Collider produce material residues?
@dmckee - Ah, my bad. Should I edit my answer to reflect this information?
Jun
22
comment Does it exist a free good molecule / atom simulation software?
@user1247 - sorry, that's 'molecular mechanics'
Jun
19
comment Do the rings in Mass Effect's mass relays (2-axis gimbal) describe a stable rotation?
Interesting question. Are you assuming the inner and outer rings are coupled, as in a 2-axis gimbal?
May
15
comment This sentence makes no sense, electrostatics and electrons moving in a conductor - current
The OP is asking about electron motion in the absence of potential.
May
15
comment This sentence makes no sense, electrostatics and electrons moving in a conductor - current
There's obvious current in that illustration.
Apr
11
comment Creation of Nuclear Isomers
very lucid answer!