Electron affinity

Electron affinity E _EA in the band diagram, where E _VAC , E _C , E _F , E _{V are} the vacuum energy, the lower conduction band edge, the Fermi energy and the upper valence band edge, respectively.

Electron affinity against atomic number

As electron affinity (EA abbreviation also e _EA or or χ) is the one referred to energy that is required to make a electron from a singly negatively charged ion to solve d. H. the ionization energy of an anion . The electron affinity is thus the energy difference between the ground state of a single neutral atom or molecule and the ground state of the associated negatively charged ion, i.e. In other words, it is the amount of energy that is released or required when an electron is taken up by the neutral atom / molecule. For solids it is the energy difference between the vacuum energy and the lower conduction band edge as shown in the picture. ${\ displaystyle \ Delta H}$

The electron affinity is therefore a measure of how strongly a neutral atom or molecule can bind an additional electron. The reverse process - the separation of an electron from a neutral atom or molecule - is called ionization and is characterized by the ionization energy. Electron affinity is one of the periodically changing properties of the elements within the periodic table of the elements.

Electron affinities of the elements

The electron affinity for an atom is given by: ${\ displaystyle E _ {\ rm {EA}}}$ ${\ displaystyle {\ rm {X}}}$

{\ displaystyle E _ {\ rm {EA}} = E ({\ rm {X}}) - E ({\ rm {X}} ^ {-})}

Occasionally a definition with the opposite sign is also used. Electron affinity values are usually given in terms of electron volts (eV) or kJ / mol.

Although the electron affinities in the periodic table vary greatly, some periodic trends are clearly recognizable. As a rule, non-metals have a greater electron affinity than metals. If a fully or partially occupied energy level is reached through the addition of an electron, the electron affinities in these groups (e.g. 14 and 17) show maxima, because particularly stable electron configurations are achieved thereby. At 3.61 eV, chlorine has the highest electron affinity of the elements.

In the case of elements which have fully occupied s-, p- or d-valence shells, the tendency to further take up electrons is naturally very low. Here energy has to be used to add more electrons to these atoms. Therefore, the alkaline earth metals, the metals of the zinc group and the noble gases have negative electron affinities.

In order to interpret the tendencies of the values, it is also helpful to know the following facts: Since an electron is attracted to the positive atomic nucleus, in a period, after decreasing atomic radius from left to right, there are ever larger values for the electron affinity, since the orbitals, and thus the distance between the outermost electron shell and the nucleus, become smaller and smaller.

Z	symbol	element	${\ displaystyle E _ {\ rm {EA}}}$ (eV)	source
1	¹ H.	hydrogen	0.754 195 (19)	Lykke KR, Murray KK & Lineberger WC, Phys. Rev. A 43 , 6104 (1991)
1	² D	deuterium	0.754 59 (8)
3	Li	lithium	0.618 049 (22)	Haeffler G., Hanstorp D., Kiyan I., Klinkmüller AE, Ljungblad U. & Pegg DJ, Phys. Rev. A 53 , 4127 (1996)
5	B.	boron	0.279 723 (25)	Scheer M., Bilodeau RC & Haugen HK, Phys. Rev. Lett. 80 , 2562 (1998)
6th	¹² C	carbon	1.262 122 6 (11)	Bresteau D., Drag C. & Blondel C., Phys. Rev. A 93 , 013414 (2016)
6th	¹³ C	carbon	1.262 113 6 (12)
8th	¹⁶ O	oxygen	1.461 113 6 (9)	Chaibi W., Peláez RJ, Blondel C., Drag C. & Delsart C., Eur. Phys. J. D 58 , 29 (2010)
	¹⁷ O		1.461 108 (4)	Blondel C., Delsart C., Valli C., Yiou S., Godefroid MR & Van Eck S., Phys. Rev. A 64 , 052504 (2001)
	¹⁸ O		1.461 105 (3)
9	F.	fluorine	3,401 189 8 (24)	Blondel C., Delsart C. & Goldfarb F., J. Phys. B: At. Mol. Opt. Phys. 34 , L281 and 2757 (2001)
11	N / A	sodium	0.547 926 (25)	Hotop H. & Lineberger WC, J. Phys. Chem. Ref. Data 14 , 731 (1985)
13	Al	aluminum	0.432 83 (5)	Scheer M., Bilodeau RC, Thøgersen J. & Haugen HK, Phys. Rev. A 57 , 1493 (1995)
14th	Si	Silicon	1.389 521 2 (8)	Chaibi W., Peláez RJ, Blondel C., Drag C. & Delsart C., Eur. Phys. J. D 58 , 29 (2010)
15th	P	phosphorus	0.746 607 (10)	Peláez RJ, Blondel C., Vandevraye M., Drag C. & Delsart C., J. Phys. B: At. Mol. Opt. Phys. 44 , 195009 (2011)
16	³² p	sulfur	2.077 104 2 (6)	Chaibi W., Peláez RJ, Blondel C., Drag C. & Delsart C., Eur. Phys. J. D 58 , 29 (2010)
16	³⁴ p	sulfur	2.077 104 5 (12)	Carette T., Drag C., Scharf O., Blondel C., Delsart C., Froese Fischer C. & Godefroid M., Phys. Rev. A 81 , 042522 (2010)
17th	Cl	chlorine	3,612 725 (28)	Berzinsh U., Gustafsson M., Hanstorp D., Klinkmüller A., Ljungblad U. & Martensson-Pendrill AM, Phys. Rev. A 51 , 231 (1995)
19th	K	potassium	0.501 459 (13)	Andersson KT, Sandström J., Kiyan IY, Hanstorp D. & Pegg DJ, Phys. Rev. A 62 , 22503 (2000)
20th	Approx	Calcium	0.024 55 (10)	Petrunin VV, Andersen HH, Balling P. & Andersen T., Phys. Rev. Lett. 76 , 744 (1996)
21st	Sc	Scandium	0.188 (20)	Feigerle CS, Herman Z. & Lineberger WC, J. Electron Spectrosc. Rel. Phenom. 23 , 441 (1981)
22nd	Ti	titanium	0.075 54 (5)	Tang R., Fu X. & Ning C., J. Chem. Phys. 149 , 134304 (2018)
23	V	Vanadium	0.527 66 (20)	Fu X., Luo Z., Chen X., Li J. & Ning C., J. Chem. Phys. 145 , 164307 (2016)
24	Cr	chrome	0.675 84 (12)	Bilodeau RC, Scheer M. & Haugen HK, J. Phys. B: At. Mol. Opt. Phys. 31 , 3885 (1998)
26th	Fe	iron	0.153 236 (34)	Chen X., Luo Z., Li J. & Ning C., Sci. Rep. 6 , 24996 (2016)
27	Co	Cobalt	0.662 26 (5)	Chen X. & Ning C., Phys. Rev. A 93 , 052508 (2016)
28	Ni	nickel	1.157 16 (12)	Scheer M., Brodie CA, Bilodeau RC & Haugen HK, Phys. Rev. A 58 , 2051 (1998)
29	Cu	copper	1.235 78 (4)	Bilodeau RC, Scheer M. & Haugen HK, J. Phys. B: At. Mol. Opt. Phys. 31 , 3885 (1998)
31	Ga	gallium	0.301 20 (11)	Gibson ND, Walter CW, Crocker C., Wang J., Nakayama W., Yukich JN, Eliav E. & Kaldor U., Phys. Rev. A 100 , 052512 (2019)
32	Ge	Germanium	1.232 676 4 (13)	Bresteau D., Babilotte Ph., Drag C. & Blondel C., J. Phys. B: At. Mol. Opt. Phys. 48 , 125001 (2015)
33	As	arsenic	0.8048 (2)	Walter CW, Gibson ND, Field RL, Snedden AP, Shapiro JZ, Janczak CM & Hanstorp D., Phys. Rev. A 80 , 014501 (2009)
34	Se	selenium	2.020 604 7 (12)	Vandevraye M., Drag C. & Blondel C., Phys. Rev. A 85 , 015401 (2012)
35	Br	bromine	3.363 588 (3)	Blondel C., Cacciani P., Delsart C. & Trainham R., Phys. Rev. A 40 , 3698 (1989)
37	Rb	Rubidium	0.485 916 (21)	Frey P., Breyer F. & Hotop H., J. Phys. B: At. Mol. Phys. 11 , L589 (1978)
38	Sr	strontium	0.052 06 (6)	Andersen HH, Petrunin VV, Kristensen P. & Andersen T., Phys. Rev. A 55 , 3247 (1997)
39	Y	yttrium	0.307 (12)	Feigerle CS, Herman Z. & Lineberger WC, J. Electron Spectrosc. Rel. Phenom. 23 , 441 (1981)
40	Zr	Zirconium	0.433 28 (9)	Fu X., Li J., Luo Z., Chen X. & Ning C., J. Chem. Phys. 147 , 064306 (2017)
41	Nb	niobium	0.917 40 (6)	Luo Z., Chen X., Li J. & Ning C., Phys. Rev. A 93 , 020501 (2016)
42	Mon	molybdenum	0.747 3 (3)	Bilodeau RC, Scheer M. & Haugen HK, J. Phys. B: At. Mol. Opt. Phys. 31 , 3885 (1998)
44	Ru	Ruthenium	1,046 38 (25)	Norquist PL, Beck DR, Bilodeau RC, Scheer M., Srawley RA & Haugen HK, Phys. Rev. A 59 , 1896 (1999)
45	Rh	Rhodium	1.142 89 (20)	Scheer M., Brodie CA, Bilodeau RC & Haugen HK, Phys. Rev. A 58 , 2051 (1998)
46	Pd	palladium	0.562 14 (12)
47	Ag	silver	1,304 47 (3)	Bilodeau RC, Scheer M. & Haugen HK, J. Phys. B: At. Mol. Opt. Phys. 31 , 3885 (1998)
49	In	Indium	0.383 92 (6)	Walter CW, Gibson ND, Carman DJ, Li Y.-G. & Matyas DJ, Phys. Rev. A 82 , 032507 (2010)
50	Sn	tin	1,112 070 (2)	Vandevraye M., Drag C. & Blondel C., J. Phys. B: At. Mol. Opt. Phys. 46 , 125002 (2013)
51	Sb	antimony	1,047 401 (19)	Scheer M., Haugen HK & Beck DR, Phys. Rev. Lett. 79 , 4104 (1997)
52	Te	Tellurium	1,970 875 (7)	Haeffler G., Klinkmüller AE, Rangell J., Berzinsh U. & Hanstorp D., Z. Phys. D 38 , 211 (1996)
53	¹²⁷ I.	Iodine	3,059 046 5 (37)	RJ Peláez, C. Blondel, C. Delsart & C. Drag, J. Phys. B: At. Mol. Opt. Phys. 42 (2009)
53	¹²⁸ I.	Iodine	3,059 052 (38)	Rothe S. et al. , J. Phys. G: Nucl. Part. Phys. 44 , 104003 (2017)
55	Cs	Cesium	0.471 630 (25)	Hotop H. & Lineberger WC, J. Phys. Chem. Ref. Data 14 , 731 (1985)
56	Ba	barium	0.144 62 (6)	Petrunin VV, Voldstad JD, Balling P., Kristensen P., Andersen T. & Haugen HK, Phys. Rev. Lett. 75 , 1911 (1995)
57	La	Lanthanum	0.55 (2)	Pan L. & Beck DR, Phys. Rev. A 93 , 062501 (2016)
58	Ce	cerium	0.57 (2)	Felton J., Ray M. & Jarrold CC, Phys. Rev. A 89 , 033407 (2014)
59	Pr	Praseodymium	0.962 (24)	Davis VT & Thompson JS, J. Phys. B: At. Mol. Opt. Phys. 35 , L11 (2002)
63	Eu	Europium	0.116 (13)	Cheng S.-B. & Castleman AW Jr, Sci. Rep. 5 , 12414 (2015)
69	Tm	Thulium	1,029 (22)	Davis VT & Thompson JS, Phys. Rev. A 65 , 010501 (2001)
71	Lu	lutetium	0.2388 (7)	Fu X., Tang R., Lu Y. & Ning C., Chinese J. Chem. Phys. 32 , 187 (2019)
72	Hf	hafnium	0.1780 (7)	Tang R., Chen X., Fu X., Wang H. & Ning C., Phys. Rev. A 98 , 020501 (R) (2018)
73	Ta	Tantalum	0.323 (12)	Feigerle CS, Corderman RR, Bobashev SV & Lineberger WC, J. Chem. Phys. 74 , 1580 (1981)
74	W.	tungsten	0.816 26 (8)	Lindahl AO, Andersson P., Diehl C., Forstner O., Klason P. & Hanstorp D., Eur. Phys. J. D 60 , 219 (2010)
75	re	rhenium	0.060 396 (64)	Chen, X., & Ning, C., J. Phys. Chem. Lett. 8 , 2735 (2017)
76	Os	osmium	1,077 80 (12)	Bilodeau RC & Haugen HK, Phys. Rev. Lett. 85 , 534 (2000)
77	Ir	iridium	1.564 36 (15)	Bilodeau RC, Scheer M., Haugen HK & Brooks RL, Phys. Rev. A 61 , 012505 (1999)
78	Pt	platinum	2.125 10 (5)
79	Au	gold	2.308 610 (25)	Andersen T., Haugen HK & Hotop H., J. Phys. Chem. Ref. Data 28 , 1511 (1999)
81	Tl	Thallium	0.377 (13)	Carpenter DL, Covington AM & Thompson JS, Phys. Rev. A 61 , 042501 (2000)
82	Pb	lead	0.356 721 (2)	Bresteau D., Drag C. & Blondel C., J. Phys. B: At. Mol. Opt. Phys. 52 , 065001 (2019)
83	Bi	Bismuth	0.942 362 (13)	Bilodeau RC & Haugen HK, Phys. Rev. A 64 , 024501 (2001)
84	Po	polonium	1.405 (61) (theoretical)	Li, Zhao, Andersson, Zhang & Chen, J. Phys. B: At. Mol. Opt. Phys. 45 , 165004 (2012)
85	At	Astatine	2.42 (12) (theoretical)
87	Fr.	Francium	0.491 (5) (theoretical)	Landau A., Eliav E., Ishikawa Y. & Kaldor U., J. Chem. Phys. 115 , 2389 (2001)

Individual evidence

↑ Entry on electron affinity . In: IUPAC Compendium of Chemical Terminology (the “Gold Book”) . doi : 10.1351 / goldbook.E01977 Version: 2.3.1.
^ Harald Ibach, Hans Lüth: Solid State Physics. Introduction to the basics . 5th edition. Springer, Berlin 1999, p. 480 .
^ Charles E. Mortimer, Ulrich Müller (ed.): Chemistry - basic knowledge of chemistry . 8th edition. Thieme, Marburg 2003, p. 95 .

[1] Entry on electron affinity . In: IUPAC Compendium of Chemical Terminology (the “Gold Book”) . doi : 10.1351 / goldbook.E01977 Version: 2.3.1.

[2] Harald Ibach, Hans Lüth: Solid State Physics. Introduction to the basics . 5th edition. Springer, Berlin 1999, p. 480 .

[3] Charles E. Mortimer, Ulrich Müller (ed.): Chemistry - basic knowledge of chemistry . 8th edition. Thieme, Marburg 2003, p. 95 .

Electron affinity

Electron affinities of the elements

See also

Individual evidence