eÐl620m / life in the universe life in the universe astrophysics – chemistry – biology –...

EÐL620M / Life in the Universe

Astrophysics – chemistry – Biology – earth-/planetary sciences

•Atoms - chemical bond

•Carbon chemical bond

•Atoms and molecules in space; Informations derived from spectroscopy

•Molecules in the universe;Existance and formation

•Interactions between light and matter ;photochemistry, photoionization, photofragmentation

•Thermochemistry in the Universe•Biochemistry

Atom:

nuclei: p, +n, 0

electron: e-

0.1 nm

0.1 10-9 m10-10 m

?

?

?No wave(?)No electron(?)

?

Standing waveElectron in an orbit

Energy

n=1

n=2

n=3

n :

0

-

2n

RE

but, Three dimension ?

2(r)

r

Þ.e. líkindasvæði 2(x,y,z)

n....... n+1 ....... n+2 ........

n

S - svigrúm

2(r,)

r

2 e- per

orbital

- Opposite spins:

E

n = 1

n = 2

n = 3

:n = 4

l = 0/s l = 1/p l = 2/d l = 3/f

::

::

::

.1x e-

H.

H: 1s1; ground state

H*: > 1s1; excited states

R2

r

Na: 1s22s22p6 3s

Na+: 1s22s22p6

screening:

3s

Na*: 1s22s22p6 3p

3p

Na**: 1s22s22p6 3d

3d

E

n = 1

n = 2

n = 3

:n = 4

l = 0/s l = 1/p l = 2/d l = 3/f

::

::

::

.

A > H.

e.g. C(6e-)

C: 1s2,2s2,2p2

C*, e.g. : 1s2,2s2,2p13s1

E

n = 1

n = 2

n = 3

:n = 4

l = 0/s l = 1/p l = 2/d l = 3/f

::

::

::

.

A > H.

e.g. C(6e-)

Relationship between atoms and valence electron orbitals

H H

21s 2

1s

1s + 1s)2

1s - 1s)2

2 x 2e-2 x 2e-

2 x atom orbitals 2 x molecular orbitals

1s + 1s)2

1s - 1s)2

+

--

-

- --

-

-

+

attractionr-forces, F-

attraction-forces, F-

repulsion-forces, F+

attraction-forces, F-

repulsion-forces, F+

netRepulsion forces:

antibonding

NetAttraction forces:

bonding:

Chemical bond

--

--+ +

2x

::

2x

2xn = 1

n = 2

n = 3

::

E::

::

::

n = 1

n = 2

n = 3

::

Es

Molecular energies (orbitals) quantized

A, AB ...... Low energy electron configurations /Ground states

A*, AB*...... High energy electron configurations/ excited states

NB!