User Allie | chat.stackexchange.com

Allie

yst 21:03

In the Debye model using BVK boundary conditions, you can't have any phonons with k-vector shorter than 2pi/L but that's generally fine because those states are very low in energy and have low DOS anyways, right

Allie

Fri 02:13

Or alternatively, so that your D.O.F. is the correct amount you expect for N atoms?

Allie

Fri 02:13

So in the Debye model, is it correct to say that you're basically treating a solid like a continuum but putting a limit on what wavelengths you consider based on the atomic spacing, so that you don't double count equivalent waves?

Allie

Fri 00:25

i hate thermodynamics

Allie

Thu 18:57

meow

Allie

Thu 02:14

(although any k-vector outside the first Brillouin zone is just a repeat)

Allie

Thu 02:13

in an infinite crystal (let's say monatomic), there is an allowed state for every possible k-vector, correct?

Allie

Thu 01:50

meow

Allie

Wed 20:48

besides ill still be a student for the next 5 years, no? a phd student

Allie

Wed 20:48

but i disagre

Allie

Wed 20:47

@TobiasFünke everyone keeps saying thi

Allie

Wed 20:35

not work on a stupid lab report

Allie

Wed 20:35

i just want to study solid state rn :(

Allie

Wed 20:35

i cant fail my classes

Allie

Wed 20:35

nooo

Allie

Wed 20:34

im so excited to be done with undergrad this semester!!!!

Allie

Wed 20:33

i dont want to do this stupid lab report

Allie

Wed 20:33

motivation is hard

Allie

Wed 20:33

hi guys

Allie

Wed 16:08

not sure if i answered ur question the other day, yes I am still working in DFT

Allie

Wed 16:08

tobias hiyas

Allie

Wed 15:53

hiiiii

Allie

Wed 01:41

id rather consult resources made by humans who know exactly what theyre doing then sift through a computers mistakes

Allie

Wed 01:41

yeah im never gonna do that

Allie

Wed 00:15

hi girls

Allie

Tue 04:08

good night

Allie

Tue 04:08

meow

Allie

Tue 03:45

are you talking to me?

Allie

Tue 01:32

im done being trapped at 0K

Allie

Tue 01:32

its cool ive always wanted ot get into this im finally dipping my toes

Allie

Tue 01:32

i like stat mech so far though

Allie

Tue 01:31

(theoretical chemist)

Allie

Tue 01:31

ive neevr heard it referred to as just the catastrophe but i guess im a FAKE physicist

Allie

Tue 01:31

ah

Allie

Tue 01:29

the catastrophe?

Allie

Tue 01:27

facepalm

Allie

Tue 01:26

i was literally about to say how convenient, FD for fermion and BE for boson. then i realized fermion comes from fermi and boson comes from bose

Allie

Tue 01:25

FD for fermions, BE for bosons

Allie

Tue 01:25

and i think that's where you get fermi-dirac and bose-einstein statistics, right?

Allie

Tue 01:24

i get it

Allie

Tue 01:24

meow

Allie

Tue 01:23

my textbook said in many cases it can be a reasonable assumption that there will be enough energy states available that at a high enough temperature the overlap is minimal

Allie

Tue 01:22

how many energy states are available, what temp were at, etc

Allie

Tue 01:22

well doesnt that depend on what the conditions are

Allie

Tue 01:16

for distinguishable independent

Allie

Tue 01:15

we were talking about non-degenerate

Allie

Feb 17 00:42

in my case they're doing it so they can separate the partition function into translational and electronic partition functions

Allie

Feb 17 00:42

yeah

Allie

Feb 17 00:32

read under "in molecular spectroscopy"

Allie

Feb 17 00:32

Born–Oppenheimer approximation

In quantum chemistry and molecular physics, the Born–Oppenheimer (BO) approximation is the best-known mathematical approximation in molecular dynamics. Specifically, it is the assumption that the wave functions of atomic nuclei and electrons in a molecule can be treated separately, based on the fact that the nuclei are much heavier than the electrons. Due to the larger relative mass of a nucleus compared to an electron, the coordinates of the nuclei in a system are approximated as fixed, while the coordinates of the electrons are dynamic. The approach is named after Max Born and his 23-year-old...

Allie

The h Bar